Water jet propulsion watercraft

ABSTRACT

A water jet propulsion watercraft includes a hull, an engine attached to the hull, a jet propulsion device arranged to be driven using an output of the engine and to jet water toward a rear of the hull from a jet port provided on an outer side of the hull, a bucket arranged to be disposed in a manner enabling movement between a forward drive position of not blocking the water jetted from the jet port of the jet propulsion device and a reverse drive position of blocking the water jetted from the jet port and, at the reverse drive position, to convert a jetting direction of the water jetted rearward from the jet port to a forward direction, a hydraulic cylinder arranged to be disposed in an interior of the hull and to move the bucket between the forward drive position and the reverse drive position, and an oil passage arranged to connect the engine and the hydraulic cylinder and to cause a lubricating oil inside of the engine to pass through as a hydraulic oil of the hydraulic cylinder.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a water jet propulsion watercraftincluding a jet unit (jet propulsion device) having an engine as a drivesource.

2. Description of the Related Art

A water jet propulsion watercraft includes a hull and a jet propulsiondevice that applies a propulsive force to the hull. An example of thewater jet propulsion device is disclosed in Japanese Unexamined PatentApplication Publication No. 06-219386. This water jet propulsion deviceincludes an impeller shaft rotated by an engine, an impeller connectedto the impeller shaft, and a jet nozzle disposed at the rear of theimpeller. By rotation of the impeller shaft, water is sucked in from awater inlet by the impeller and the water is jetted rearward from thejet nozzle. The propulsive force is thereby applied to the hull.

A deflector (steering nozzle) for changing a direction of the waterjetted from the jet nozzle to right and left directions is disposed atthe rear of the jet nozzle. The water jetted from the jet nozzle passesthrough the deflector. As a result of the water flow from the jet nozzlebeing changed rightward or leftward by the deflector in this process, aheading direction of the hull can be changed.

A bucket for reverse drive is disposed near the deflector. The bucket isprovided in a manner enabling it to move up and down about a rotationalaxis line parallel to a right/left direction of the hull. The bucket isthereby arranged to be capable of moving up and down between an actionposition at the rear of the deflector and a retreated position retreatedupward from the action position. When the bucket is at the retreatedposition, the water from the deflector is jetted to the rear of the hulland a forward-directed propulsive force is applied to the hull. On theother hand, when the bucket is at the action position at the rear of thedeflector, the bucket blocks the rear of the deflector. The water fromthe deflector is changed in direction to a forward direction by thebucket in this case. The water is thereby jetted toward the front of thehull and a rearward-directed propulsive force is thus applied to thehull.

The bucket is moved up and down by being driven by a hydraulic cylinder.The hydraulic cylinder is disposed near the jet nozzle. The hydrauliccylinder includes a piston, a cylindrical main cylinder unit that housesthe piston, and a rod connected to the piston and protruding out fromthe main cylinder unit. Two oil chambers, partitioned by the piston, areformed inside the main cylinder unit. The piston undergoes reciprocatingmotion by entry and exit of oil into and from the two oil chambers. Therod undergoes reciprocating motion along with the reciprocating motionof the piston. An oil seal is disposed between the rod and the maincylinder unit and prevents oil inside the main cylinder unit fromleaking from between the rod and the main cylinder unit. The rod isconnected to the bucket. By the rod undergoing reciprocating motion, thebucket can be swung about the rotational axis line. The bucket isthereby moved up and down.

SUMMARY OF THE INVENTION

The inventors of preferred embodiments of the present inventiondescribed and claimed in the present application conducted an extensivestudy and research regarding a water jet propulsion watercraft, such asthe one described above, and in doing so, discovered and firstrecognized new unique challenges and maintenance issues as described ingreater detail below.

That is, the hydraulic cylinder is disposed at an exterior of the hulland is immersed in water. There is thus a possibility of rust and otherforeign matter adhering onto the rod of the hydraulic cylinder. Whenforeign matter adheres onto the rod, the foreign matter adhered onto therod contacts the oil seal when the bucket is displaced and may damagethe oil seal.

Also, the oil in the hydraulic cylinder for driving the bucket(hydraulic oil) undergoes aging degradation. Thus, preferably, exchangeof the oil is enabled. However, with an arrangement where the hydrauliccylinder is disposed near the jet nozzle, the hydraulic cylinder isimmersed in water. The oil must thus be exchanged after the water jetpropulsion watercraft is moved to dry land and an outer surface of thehydraulic cylinder is washed, and thus maintenance of the water jetpropulsion watercraft was troublesome.

Thus, to resolve these maintenance issues, the inventors of the presentapplication studied an arrangement in which the bucket drive hydrauliccylinder is disposed inside the hull and found the following issues inthis process.

To install the bucket drive hydraulic cylinder inside the hull, a spacefor the hydraulic cylinder must be provided inside the hull. However,the space inside the hull is determined according to various designconditions. The space inside the hull thus cannot be easily enlargedwithout careful consideration just because there is a desire to installthe bucket drive hydraulic cylinder inside the hull. It is thusdifficult to secure an installation space for the bucket drive cylinder.

With the water jet propulsion watercraft, in addition to the spaceinside the hull being small, a space that is partitioned from theexterior must be formed inside the hull (engine room) so that seawateror other water does not enter. This makes the restriction on theinstallation space for various components extremely severe. Especially,in a small-scale water jet propulsion watercraft in which a seat isdisposed above the engine and a rider straddles the seat, the interiorof the hull is extremely limited because the size of the hull is small.For example, only a narrow space in which a maintenance worker canbarely put his/her hand is left inside the hull.

Meanwhile, with the arrangement in which the hydraulic cylinder isdisposed inside the hull, adhesion of foreign matter onto the rod can beprevented. Moreover, a work of exchanging the oil can be performedinside the hull with the water jet propulsion watercraft floating on thewater as it is and without having to wash the external surface of thehydraulic cylinder. However, the oil exchange work is still troublesomebecause the work must be performed within the narrow interior of thehull. The trouble of performing maintenance on the water jet propulsionwatercraft is thus actually not reduced so much.

Thus, it is difficult to install the bucket drive hydraulic cylinderinside the hull and the maintenance of the hydraulic cylinder istroublesome even if the hydraulic cylinder can be installed inside thehull.

An arrangement, with which the bucket drive hydraulic cylinder isdisposed in the narrow space that is partitioned from the exterior so asnot to let water enter, is unique to the water jet propulsionwatercraft. The above issue is thus non-existent in an apparatus that isused other than on water (on land or in air) and is an issue unique tothe water jet propulsion watercraft.

In order to overcome the previously unrecognized and unsolvedmaintenance issues described above, a preferred embodiment of thepresent invention provides a water jet propulsion watercraft thatincludes, a hull, an engine attached to the hull, a jet propulsiondevice arranged to be driven using an output of the engine and to jetwater toward a rear of the hull from a jet port provided on an outerside of the hull, a bucket arranged to be movable between a forwarddrive position of not blocking the water jetted from the jet port of thejet propulsion device and a reverse drive position of blocking the waterjetted from the jet port and, at the reverse drive position, to converta jetting direction of the water jetted rearward from the jet port to aforward direction, a hydraulic cylinder disposed in an interior of thehull and arranged to move the bucket between the forward drive positionand the reverse drive position, and an oil passage arranged to connectthe engine and the hydraulic cylinder and to cause a lubricating oil inan inside of the engine to pass through as a hydraulic oil of thehydraulic cylinder.

According to the present water jet propulsion watercraft, the hydrauliccylinder is provided in the interior of the hull and the hydrauliccylinder can thus be prevented from constantly contacting water.Adhesion of rust and other foreign matter on various portions of thehydraulic cylinder can thereby be prevented. Damaging of variousportions of the hydraulic cylinder due to the foreign matter duringdriving of the hydraulic cylinder can thus be prevented.

The lubricating oil of the inside of the engine is supplied to thehydraulic cylinder via the oil passage and used as the hydraulic oil ofthe hydraulic cylinder. A lubricating oil supply system of the inside ofthe engine and a hydraulic oil supply system for the hydraulic cylinderare thus combined. The lubricating oil supply system and the hydraulicoil supply system can thereby be arranged using an apparatus in common(for example, an oil pump). The number of components inside the hull canthus be made small. Installation space restrictions are severe with thewater jet propulsion watercraft because, in addition to a space insidethe hull being small, a space partitioned from the exterior must beformed so that water does not enter inside the hull (engine room). Eveninside the hull with such severe installation space restrictions, thehydraulic oil supply system that is low in the number of components andis thus space-saving can be installed along with the hydraulic cylinder.

For example, in a case where the lubricating oil supply system and thehydraulic oil supply system are formed separately, an oil pump, etc.,must be provided in each of these systems. The number of components tobe housed inside the hull thus becomes large. Increase of the number ofcomponents causes an increase of installation space and consequently, itbecomes impossible to install an independent hydraulic oil supply systemtogether with the bucket drive hydraulic cylinder inside the hull.

With the present preferred embodiment of the present invention, theinside of the engine communicates with the inside of the hydrauliccylinder via the oil passage, and the lubricating oil that lubricatesthe inside of the engine is also used as the hydraulic oil of thehydraulic cylinder. Thus, by exchanging the used lubricating oil of theinside of the engine with new lubricating oil, the hydraulic oil of thehydraulic cylinder can be exchanged at the same time. Specialized workfor exchanging the hydraulic oil inside the hydraulic cylinder is thusmade unnecessary and the work of exchanging the oil inside the hydrauliccylinder can practically be omitted. The trouble of performingmaintenance on the water jet propulsion watercraft can thus be lessened.

As described above, by the arrangement of using the lubricating oil forlubricating the inside of the engine in common as the hydraulic oil ofthe hydraulic cylinder, the hydraulic cylinder and the hydraulic oilsupply system therefore can be housed in the narrow space inside thehull and facilitation of maintenance can be achieved at the same time.

Preferably, a preferred embodiment of the present invention furtherincludes, a cable arranged to transmit a driving force of the hydrauliccylinder to the bucket. According to this arrangement, the driving forceof the hydraulic cylinder disposed in the interior of the hull can betransmitted via the cable to the bucket at the exterior of the hull.

The cable includes, for example, an outer cable disposed across an innerside and an outer side of the hull, and an inner cable disposed at aninner side of the outer cable and arranged to be slidable with respectto the outer cable. According to this arrangement, the inner cable canbe protected by the outer cable. By smoothing an inner peripheralsurface of the outer cable, frictional resistance between the outercable and the inner cable can be reduced. The inner cable can thereby beslid smoothly. Consequently, driving of the bucket can be performed muchmore smoothly.

Preferably, in a preferred embodiment of the present invention, thehydraulic cylinder includes, a cylinder portion, a piston portionarranged to slide along an inner wall of the cylinder portion, and a rodportion connected to the piston portion, and the rod portion is arrangedto move in a substantially front/rear direction of the hull. Accordingto this arrangement, the rod portion is disposed to move in thesubstantially front/rear direction that is perpendicular orsubstantially perpendicular to an up/down direction, which is avibration direction of the hull. The rod portion can thereby beprevented from changing in position in synchronization with vibration inthe up/down direction of the hull. In the case where the engine isdisposed along the front/rear direction of the hull, the elongatecylinder portion can be disposed so as to be parallel or substantiallyparallel to the engine in a right/left direction. The hydraulic cylindercan thereby be positioned near the engine, thus effective use can bemade of the space inside the hull. The hull (a lateral width of theinternal hull space) can thereby be made more compact. In other words,the hydraulic cylinder can be housed in the limited space inside acompact hull.

In this case, the rod may be connected to the bucket via the cable. Therod moves in the front/rear direction and thus, for example, the cablemay be disposed to transmit the front/rear direction movement as it isto the bucket. In this case, the cable can be disposed inside the hullwithout being bent to the right or left. The cable can thus movesmoothly and the movement of the bucket can be performed much moresmoothly.

Preferably, in a preferred embodiment of the present invention, theengine includes, a crankshaft, and an oil pump arranged to be drivenusing a rotation of the crankshaft and to circulate the lubricating oilinside the engine, and the oil pump is arranged to feed the lubricatingoil to the hydraulic cylinder. According to this arrangement, the needto provide a separate oil pump just for supplying oil to the hydrauliccylinder is eliminated and the number of components can be decreasedaccordingly.

Preferably, the oil pump is arranged to be driven with the rotation ofthe crankshaft. According to this arrangement, the oil pump can bedriven using the driving force of the engine.

Preferably, a preferred embodiment of the present invention furtherincludes, an oil storage portion arranged to store the lubricating oiltherein, and a relief valve arranged to be able to release thelubricating oil fed to the hydraulic cylinder by the oil pump to the oilstorage portion. According to this arrangement, the relief valve can beactuated when a discharge pressure of the oil pump increases with anincrease of the rotational speed of the engine. The lubricating oil fromthe oil pump can thereby be released to the oil storage portion.Consequently, a pressure of the lubricating oil (hydraulic oil) fed tothe hydraulic cylinder can be prevented from becoming excessively high.

Preferably, in a preferred embodiment of the present invention, the oilstorage portion is provided at a lower portion of the engine and belowthe relief valve. According to this arrangement, the excess oil releasedby the relief valve can be returned to the oil storage portion below therelief valve by use of gravity.

Preferably, in a preferred embodiment of the present invention, the oilpump includes, a first oil pump arranged to deliver the lubricating oilfrom the oil storage portion to an inside of the engine to lubricate theinside of the engine, and a second oil pump arranged to recover thelubricating oil that has lubricated the inside of the engine into theoil storage portion, and the second oil pump is arranged to have a lowerdischarge pressure than a discharge pressure of the first oil pump andis arranged to feed the lubricating oil to the hydraulic cylinder.

The second oil pump is a pump arranged to recover the lubricating oil tothe oil storage portion and the lubricating oil discharge pressure maybe low because it suffices that the pump be able to suck in thelubricating oil. On the other hand, the first oil pump needs to pump thelubricating oil into the inside of the engine and thus its lubricatingoil discharge pressure needs to be high. Thus, in regard to thelubricating oil discharge pressure, that of the second oil pump may belower than that of the first oil pump. By being arranged to feed the oilinto the hydraulic cylinder by the second oil pump, feeding of thelubricating oil into hydraulic cylinder at an excessive high pressurecan be prevented.

Preferably, in a preferred embodiment of the present invention, thehydraulic cylinder includes, a cylinder portion, and a piston portionarranged to be slidable along an inner wall of the cylinder portion andto be driven to displace the bucket between the forward drive positionand the reverse drive position, the water jet propulsion watercraftfurther includes, a valve disposed in the oil passage and arranged tochange a drive direction of the piston portion by changing a flowdirection of the lubricating oil in the oil passage, and a switcharranged to be operable by a rider, and the valve is arranged to changethe drive direction of the piston in response to the operation of theswitch. According to this arrangement, the bucket can be moved readilyto the forward drive position or the reverse drive position by operatingthe switch. For example, by operating the switch while the water jetpropulsion watercraft moves forward, the bucket can be positioned at thereverse drive position. The bucket can thereby used as a decelerationaid apparatus of the water jet propulsion watercraft.

A preferred embodiment of the present invention preferably furtherincludes, a control unit arranged to control the valve and the engine,and a rotational speed detection unit arranged to detect the rotationalspeed of the engine, and the control unit is arranged to lower therotational speed of the engine to less than the predetermined value andthereafter control the valve to change the drive direction of the pistonportion when the rotational speed of the engine is not less than apredetermined value and the rider operates the switch. According to thisarrangement, when the rotational speed of the engine is not less thanthe predetermined value and thus a water flow jetted from the jet portis strong, movement of the bucket against a force of the water flow canbe avoided. In this case, the bucket is moved after the rotational speedof the engine is decreased to less than the predetermined value and thewater flow jetted from the jet port is weakened. The water flow jettedfrom the jet port can thus be prevented from applying an excessive loadto the bucket and the bucket drive hydraulic cylinder. Consequently,breakage of the bucket and the hydraulic cylinder can be prevented. Forexample, that the engine rotational speed is not more than thepredetermined value is made a condition for moving the bucket from theforward drive position to the reverse drive position during movingforward of the water jet propulsion watercraft. Breakage of the bucketand the hydraulic cylinder, for example, in the case of using the bucketas the deceleration aid apparatus of the water jet propulsion watercraftcan thereby be prevented.

When the rotational speed of the engine is low, rotational speeds ofrespective rotating portions, such as the crankshaft, cam, etc., insidethe engine are low and it thus suffices for the lubricating oil suppliedto these rotating portions to be low in amount or pressure. A portion ofthe lubricating oil inside the engine is thus arranged to be supplied tothe hydraulic cylinder when it suffices for the supply amount of thelubricating oil supplied to the respective portions inside the engine tobe low. The lubricating oil inside the engine can thus be supplied tothe hydraulic cylinder without placing a burden on the respectiveportions inside the engine. The lubricating oil can thereby be used fordriving of the hydraulic cylinder without lowering durability of theengine.

Preferably, the water jet propulsion watercraft further includes, a pairof steering handles for steering by the rider, and an accelerator leverprovided at one of the pair of steering handles and operated by therider. In this case, the switch is preferably provided near the other ofthe pair of steering handles. According to this arrangement, the ridercan operate the accelerator lever and the switch with different hands.The rider can thus operate the switch without letting go of theaccelerator lever.

In a preferred embodiment of the present invention, the water jetpropulsion watercraft further includes, a detection unit arranged todetect the position of the bucket, and the control unit is arranged tocontrol the valve to stop the flow of oil into the hydraulic cylinderwhen the bucket is positioned at the forward drive position or thereverse drive position. According to this arrangement, the hydrauliccylinder can be prevented from generating an unnecessary driving forcewhen the bucket is positioned at the reverse drive position or theforward drive position and there is no need to move the bucket.

Preferably, the water jet propulsion watercraft further includes adisplay unit capable of displaying the position of the bucket detectedby the detection unit. According to this arrangement, the position ofthe bucket can be recognized readily by the display unit.

Preferably, the display unit is arranged to be capable of opticallydisplaying the position of the bucket while the bucket is moving betweenthe reverse drive position and the forward drive position. According tothis arrangement, the rider can readily recognize the position of thebucket that is moving.

The detection unit may be attached to the hydraulic cylinder and bearranged to detect a drive amount driven by the hydraulic cylinder.According to this arrangement, the position of the bucket can bedetermined by the control unit, etc., based on the detected drive amountof the hydraulic cylinder.

Preferably, in a preferred embodiment of the present invention, thehydraulic cylinder is disposed near the engine in an interior of thehull. According to this arrangement, the oil passage can be made short.The space occupied by the oil passage inside the hull can thereby besignificantly reduced. By lessening the space occupied by the oilpassage in the water jet propulsion watercraft with which the interiorof the hull is narrow, a degree of freedom of design of positioning ofcomponents inside the hull can be increased.

Preferably, in a preferred embodiment of the present invention, thehydraulic cylinder is supported by the engine. According to thisarrangement, the oil passage can be disposed close to the engine and theoil passage can be made shorter. Further, a hydraulic piping (the oilpassage) can be disposed near the engine and effective use can thus bemade of the space inside the hull.

Preferably, in a preferred embodiment of the present invention, thehydraulic cylinder is disposed inward relative to both ends of theengine in a width direction of the engine in plan view. According tothis arrangement, the engine and the hydraulic cylinder can be preventedfrom becoming large as a whole in the width direction (right/leftdirection). Especially, in a straddle type, small-scale water jetpropulsion watercraft, the seat is disposed above the engine andfootrests for the rider are disposed at both right and left sides of theengine. Thus, if the engine and other apparatuses disposed below theseat are large in the width direction, the width of the seat becomeslarge. When the width of the seat is large, it is not easy for a riderrelatively small to straddle the seat. In such a straddle type water jetpropulsion watercraft, to suppress the width of the seat brings anadvantage to facilitate boarding and exiting of the water jet propulsionwatercraft.

Preferably, in a preferred embodiment of the present invention, thehydraulic cylinder is supported by an upper portion of the engine.According to this arrangement, the hydraulic cylinder can be positionedby making use of space above the engine and the support structure can bemade robust. Further, maintainability of the hydraulic cylinder can beimproved because the hydraulic cylinder can be touched readily fromabove the hull. Even if water happens to enter inside the hull,immersion of the hydraulic cylinder in water can be prevented.

Preferably, in a preferred embodiment of the present invention, adirection in which the cable is pushed and pulled by the hydrauliccylinder is substantially parallel to an axial direction of the cylinderportion of the hydraulic cylinder. According to this arrangement, thecable can be disposed substantially parallel to the axial direction ofthe cylinder portion. The cable can thereby be disposed compactly insidethe hull.

Preferably, in this case, the cable is disposed along the front/reardirection of the hull. Space in the right/left direction of the hullthat is occupied by the cable inside the hull can thereby be reduced.

A preferred embodiment of the present invention preferably furtherincludes, a seat to be straddled by a rider, and the hydraulic cylinderis disposed below the seat. This arrangement can be appliedadvantageously, for example, to a straddle type, small-scale water jetpropulsion watercraft. With such a jet propulsion watercraft, the spaceinside the hull is a narrow space below the seat. Thus, the installationspace for the hydraulic cylinder is extremely limited. The hydraulic oilsupply system that makes use of the lubricating oil supply system forthe engine can be disposed along with the hydraulic cylinder in thelimited space. It thereby becomes possible to install the bucket drivehydraulic cylinder inside the hull in the straddle type, small-scalewater jet propulsion watercraft.

In a preferred embodiment of the present invention, the water jetpropulsion watercraft preferably further includes, an air introductionportion arranged to introduce air into an interior of the hull, the airintroduction portion extending from an upper portion of the hull tobelow the interior of the hull in which the engine is disposed, and thehydraulic cylinder is disposed upward relative to a lower end portion ofthe air introduction portion. According to this arrangement, when waterenters from the air introduction portion, the water drops below from thelower end portion of the air introduction portion. Consequently, thewater that has entered into the hull from the air introduction portioncan be prevented from adhering onto the hydraulic cylinder.

Preferably, in a preferred embodiment of the present invention, thehydraulic cylinder is disposed at a rear relative to the engine.According to this arrangement, the hydraulic cylinder can be disposedclose to the bucket. The cable or other connecting member arranged toconnect the hydraulic cylinder to the bucket can thereby be made short.By the connecting member being made short, an installation space for theconnecting member inside the hull can be made small.

Preferably, in this case, a partition plate that partitions the interiorof the hull in the front/rear direction is further included, the engineis disposed at the front relative to the partition plate, and thehydraulic cylinder is disposed at the rear relative to the partitionplate. According to this arrangement, the hydraulic cylinder can bedisposed closer to the bucket.

A preferred embodiment of the present invention preferably furtherincludes, a position holding member arranged to hold the bucket at theforward drive position. According to this arrangement, the bucket can beheld at the forward drive position by the position holding member. Theload of the hydraulic cylinder can be lessened because the bucket doesnot have to be held at the forward drive position by the force of thehydraulic cylinder.

Preferably, in a preferred embodiment of the present invention, thehydraulic cylinder includes, a cylinder portion, a piston portionarranged to slide along an inner wall of the cylinder portion, and a rodportion connected to the piston portion, and a portion of the rodportion housed inside the cylinder portion is greater when the bucket isat the forward drive position than when the bucket is at the reversedrive position. Ordinarily, the bucket is positioned at the forwarddrive position for a longer time than at the reverse drive position. Atime during which the greater portion of the rod portion is housed inthe cylinder portion can thus be made long and adhesion of dust andother foreign matter on the rod portion can be reliably prevented.

In a preferred embodiment of the present invention, the hydrauliccylinder includes, a cylinder portion, a piston portion arranged toslide along an inner wall of the cylinder portion, and a rod portionconnected to the piston portion, and the water jet propulsion watercraftfurther includes, a link mechanism connected to the rod portion of thehydraulic cylinder and the cable and arranged to move the cable in adirection opposite a movement direction of the rod portion. According tothis arrangement, a movement distance of the bucket can thereby beadjusted based on adjustment of a length of the link mechanism.

Other elements, features, steps, characteristics and advantages of thepresent invention will become more apparent from the following detaileddescription of the preferred embodiments with reference to the attacheddrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of an overall arrangement of a water jetpropulsion watercraft according to a first preferred embodiment of thepresent invention.

FIG. 2 is a sectional view for describing in detail an arrangement of aninterior of a hull of the water jet propulsion watercraft according tothe first preferred embodiment.

FIG. 3 is a sectional view for describing in detail the arrangement ofthe interior of the hull of the water jet propulsion watercraftaccording to the first preferred embodiment.

FIG. 4 is a sectional view of an engine of the water jet propulsionwatercraft according to the first preferred embodiment as viewed fromthe front.

FIG. 5 is a plan view of principal portions around the engine and abucket of the water jet propulsion watercraft according to the firstpreferred embodiment.

FIG. 6 is a perspective view for describing an arrangement of a vicinityof a steering unit of the water jet propulsion watercraft according tothe first preferred embodiment.

FIG. 7 is a perspective view for describing an arrangement around a leftgrip of the steering unit of the water jet propulsion watercraftaccording to the first preferred embodiment.

FIG. 8 is a sectional view for describing an arrangement of a forwarddrive switch and a reverse drive switch of the water jet propulsionwatercraft according to the first preferred embodiment.

FIG. 9 is a sectional view for describing a structure of a bucketoperation indication lamp portion of the water jet propulsion watercraftaccording to the first preferred embodiment.

FIG. 10 is a sectional view for describing a structure of a notificationlamp portion of the water jet propulsion watercraft according to thefirst preferred embodiment.

FIG. 11 is a perspective view of an arrangement of a deceleration aidlever of the water jet propulsion watercraft according to the firstpreferred embodiment.

FIG. 12 is a block diagram for describing an electrical arrangementrelated to an ECU.

FIG. 13 is a flowchart for describing control for moving the bucket froma forward drive position to a reverse drive position.

FIG. 14 is a flowchart for describing control for moving the bucket fromthe reverse drive position to the forward drive position.

FIG. 15 is a sectional view of an overall arrangement of a water jetpropulsion watercraft according to a second preferred embodiment of thepresent invention.

FIG. 16 is a sectional view of the overall arrangement of the water jetpropulsion watercraft according to the second preferred embodiment.

FIG. 17 is a diagram for describing an arrangement of a link mechanismof the water jet propulsion watercraft according to the second preferredembodiment.

FIG. 18 is a perspective view for describing an arrangement of avicinity of a steering unit of the water jet propulsion watercraftaccording to the second preferred embodiment.

FIG. 19 is a diagram for describing an arrangement around aboard of thewater jet propulsion watercraft according to the second preferredembodiment.

FIG. 20 is a sectional view for describing a structure of a bucketoperation indication lamp portion of the water jet propulsion watercraftaccording to the second preferred embodiment.

FIG. 21 is a block diagram for describing an electrical arrangementrelated to an ECU of the water jet propulsion watercraft according tothe second preferred embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First PreferredEmbodiment

FIG. 1 is a side view of an overall arrangement of a water jetpropulsion watercraft according to a first preferred embodiment of thepresent invention. In the figure, FWD indicates a forward drivedirection of the marine vessel, and BWD indicates a reverse drivedirection of the marine vessel.

The water jet propulsion watercraft 1 includes a hull 2, an engine 3, afuel tank 4, and a jet propulsion device 51. In the followingdescription, “front/rear,” “up/down,” and “right/left” shall refer tothe front/rear, up/down, and right/left as viewed from a rider riding onthe water jet propulsion watercraft 1 and facing forward.

The hull 2 includes a deck 2 a, disposed at an upper portion, and a hullbody 2 b, disposed at a lower portion. An engine room 2 c is arranged inan interior of the hull 2. The engine room 2 c houses an engine 3 thatis driven to propel the hull 2, and a fuel tank 4. A bulkhead 2 d,extending vertically upward from a bottom portion of the hull body 2 b,is provided at a rear portion of the interior of the hull 2. Thebulkhead 2 d is disposed at the rear portion of the engine room 2 c andpartitions the interior of the hull 2 in a front/rear direction. Thebulkhead 2 d has a function of preventing the occurrence of rolling,which is a phenomenon by which the hull 2 is twisted about an axial lineparallel to the front/rear direction (FWD arrow direction and BWD arrowdirection). The bulkhead 2 d is an example of a “partition plate”according to a preferred embodiment of the present invention.

An air ventilation hose 5, extending downward from the deck 2 a to alower portion of the engine room 2 c, is provided in the engine room 2c. The air ventilation hose 5 is an example of an “air introductionportion” according to a preferred embodiment of the present invention.The air ventilation hose 5 is provided for performing ventilation of(introduction of air into) the interior of the engine room 2 c. The airventilation hose 5 is a tubular member disposed in front of the engine3.

FIG. 2 is a sectional view for describing in detail an arrangement ofthe interior of a hull 2 of the water jet propulsion watercraft 1according to the first preferred embodiment. The engine 3 is, forexample, an in-line four-cylinder engine. The engine 3 includes acrankshaft 31 and a crankcase 32. The crankshaft 31 is disposed toextend in the front/rear direction. In the following, a rotational speedof the crankshaft 31 shall be referred to simply as a “rotational speedof the engine 3.”

The crankcase 32 of the engine 3 is attached to the hull body 2 b. Thecrankcase 32 houses and rotatably supports a large portion of a frontportion side of the crankshaft 31. An oil pan 32 a, storing oil(lubricating oil) that lubricates an inside of the engine 3, is providedat a lower portion of the crankcase 32 (engine 3). The oil is an exampleof a “lubricating oil” and a “hydraulic oil” according to a preferredembodiment of the present invention. The oil pan 32 a is an example ofan “oil storage portion” according to a preferred embodiment of thepresent invention.

The engine 3 is provided with a feed pump 34 and a scavenge pump 35 forcirculating the oil inside of the engine 3. The feed pump 34 deliversthe oil, stored in the oil pan 32 a, into the inside of the engine 3.The scavenge pump 35 sucks in the oil, which has lubricated respectiveportions of the engine 3, to recover the oil, which has lubricated theinside of the engine 3, into the oil pan 32 a. A discharge pressure ofthe scavenge pump 35 is set lower than a discharge pressure of the feedpump 34. The feed pump 34 is an example of an “oil pump” and a “firstoil pump” according to a preferred embodiment of the present invention,and the scavenge pump 35 is an example of the “oil pump” and a “secondoil pump” according to a preferred embodiment of the present invention.

A rotation shaft of the feed pump 34 and a rotation shaft of thescavenge pump 35 are respectively arranged to be coaxial to thecrankshaft 31. The rotation shaft of the feed pump 34 and the rotationshaft of the scavenge pump 35 are connected to the crankshaft 31 and arearranged to be driven integrally with the crankshaft 31 with therotation of the crankshaft 31. The feed pump 34 and the scavenge pump 35may instead be connected respectively via a gear, etc., to thecrankshaft 31.

A pair of couplings 33 a and 33 b are provided at the rear of thecrankshaft 31. The couplings 33 a and 33 b connect the crankshaft 31 andan impeller shaft 6 and transmit the rotation of the crankshaft 31 tothe impeller shaft 6. The impeller shaft 6 extends rearward from theengine room 2 c and through the bulkhead 2 d. A vicinity of a rear endportion of the impeller shaft 6 is connected to the jet propulsiondevice 51.

The jet propulsion device 51 applies a propulsive force to the hull 2 bybeing arranged to jet water and is disposed at an outer side of a rearportion of the hull 2. The jet propulsion device 51 includes theimpeller housing 8 a, an impeller 7, a nozzle 8 b, and a deflector 9.

The impeller housing 8 a is a tubular member disposed at the rearportion of the hull 2 and is connected to a rear portion of a watersuction portion 2 e of the hull 2. The water suction portion 2 e isdisposed between the bulkhead 2 d and the impeller housing 8 a anddefines a water passage that opens to a bottom surface of the hull body2 b. The water suction portion 2 e communications with the impellerhousing 8 a.

The impeller shaft 6 extends to the rear of the water suction portion 2e and a rear end portion of the impeller shaft 6 is disposed inside theimpeller housing 8 a.

The impeller 7 is attached to the vicinity of the rear end portion ofthe impeller shaft 6. The impeller 7 is disposed in an inside of theimpeller housing 8 a, sucks in water below a water surface from thewater suction portion 2 e, and jets the sucked-in water rearward fromthe tubular nozzle 8 b provided at the rear of the impeller housing 8 a.

The deflector 9 preferably has a tubular shape and is provided at therear of the nozzle 8 b. The deflector 9 is provided for converting a jetstream of the water jetted rearward from the nozzle 8 b to right andleft directions. The nozzle 8 b and the deflector 9 are an example of a“jet port” according to a preferred embodiment of the present invention.The deflector 9 is capable of rotating to the right and left withrespect to the nozzle 8 b (hull 2).

A bucket 10 is disposed near the deflector 9. The bucket 10 is arrangedto be swingable up and down with respect to the deflector 9 about anaxial portion 52 extending in a right/left direction. By the bucket 10being moved to the rear of the deflector 9, a jetting direction of thewater jetted rearward from the nozzle 8 b and the deflector 9 isconverted forward. In the first preferred embodiment, although thebucket 10 is attached to the deflector 9, it may be attached to theimpeller housing 8 a instead.

The water jet propulsion watercraft 1 includes a hydraulic cylinder 14,disposed inside the engine room 2 c of the hull 2, and a wire cable 11,transmitting a driving force of the hydraulic cylinder 14, to the bucket10.

The wire cable 11 is connected to an upper side portion of the bucket10. The wire cable 11 is an example of a “cable” according to apreferred embodiment of the present invention. The wire cable 11 extendsto the outer side of the hull 2 from the interior of the hull 2 andconnects the hydraulic cylinder 14 and the bucket 10. That is, the wirecable 11 connects the hydraulic cylinder 14 at the inner side of thehull 2 and the bucket 10 disposed at the outer side of the hull 2. Adriving force of the hydraulic cylinder 14 is thereby transmitted to thebucket 10.

FIG. 3 is a sectional view for describing in detail the arrangement ofthe interior of the hull 2 of the water jet propulsion watercraft 1according to the first preferred embodiment. Referring to FIG. 2 andFIG. 3, with the wire cable 11 being moved in the front/rear directionby the hydraulic cylinder 14, the bucket 10 rotates (moves) between areverse drive position A at the rear of the deflector 9 (see FIG. 2) anda forward drive position B above the deflector 9 (see FIG. 3).

The bucket 10 at the forward drive position B does not block the waterjetted from the nozzle 8 b. When the bucket 10 is positioned at theforward drive position B, the water that is jetted rearward from thedeflector 9 is jetted rearward without hitting the bucket 10. Apropulsive force that propels the hull 2 forward is thereby applied tothe hull 2.

On the other hand, the bucket 10 at the reverse drive position A blocksthe water jetted from the nozzle 8 b. When the bucket 10 is positionedat the reverse drive position A, the water jetted rearward from thedeflector 9 hits the bucket 10 and is changed in direction to theforward direction. Direction of the water is converted not just simplyforward but diagonally forward in plan view or diagonally forward inside view or other direction that includes at least a forward directedvector. The hull 2 can thereby be decelerated or propelled rearward.

As shown in FIG. 3, a rear end of a spring member 12, preferably definedby a compression coil spring, for example, is attached to the bucket 10.The spring member 12 is an example of a “position holding member”according to a preferred embodiment of the present invention. A frontend of the spring member 12 is attached to an outer side surface of thenozzle 8 b. The spring member 12 has a function of holding the bucket 10at the forward drive position B.

FIG. 4 is a sectional view of the engine 3 and principal portions aroundthe engine 3 as viewed from the front. Referring to FIG. 2 and FIG. 4,the engine 3 includes a cylinder body 53 disposed above the crankcase32, an exhaust pipe 37, connected to a left end portion of the cylinderbody 53, and a head cover 54 disposed above the cylinder body 53.

The exhaust pipe 37 is disposed at an upper portion of the engine 3. Thehydraulic cylinder 14 is disposed in the engine room 2 c and issupported by the head cover 54 near the exhaust pipe 37.

FIG. 5 is a plan view of principal portions around the engine 3 and thebucket 10. The exhaust pipe 37 is disposed at a right side (X2 arrowdirection side) of the engine 3 as viewed from the front. The exhaustpipe 37 is connected to a water lock 13 that prevents reverse flow ofwater. An air intake chamber 36 is disposed at a left side (X1 arrowdirection side) of the engine 3 as viewed from the front.

The hydraulic cylinder 14 is disposed parallel or substantially parallelto the air intake chamber 36 in the right/left direction. With theengine 3 at the center, the hydraulic cylinder 14 is disposed at a sideopposite the side at which the air intake chamber 36 is disposed.

In plan view, the hydraulic cylinder 14 is disposed inward relative toboth ends of the engine 3 in a width direction of the engine 3 (X1 arrowdirection and X2 arrow direction). As shown in FIG. 1, the hydrauliccylinder 14 is disposed upward relative to a lower end portion 5 a ofthe air ventilation hose 5.

The wire cable 11 extends substantially parallel to the front/reardirection of the hull 2 and an axial direction of the hydraulic cylinder14 and is pushed and pulled by the hydraulic cylinder 14 in a directionsubstantially parallel to the front/rear direction of the hull 2. Thehydraulic cylinder 14 is disposed upward relative to a rear end portionof the wire cable 11.

As shown in FIG. 2, the hydraulic cylinder 14 includes a cylinderportion 140, a piston portion 141 arranged to slide along an inner wallof the cylinder portion 140, and a rod portion 142 connected to thepiston portion 141.

The cylinder portion 140 extends along the front/rear direction of thehull 2 (FWD arrow direction and BWD arrow direction) and is arranged toa tubular form with both ends closed. The cylinder portion 140 is fixedto the head cover 54 (upper portion of the engine 3).

An inside of the cylinder portion 140 includes a front oil chamber 140 awhich is a FWD arrow direction side portion partitioned by the pistonportion 141, and a rear oil chamber 140 b which is a BWD arrow directionside portion.

The rod portion 142 extends in the front/rear direction. A front endportion of the rod portion 142 is connected to the piston portion 141.The rod portion 142 penetrates through a rear end portion of thecylinder portion 140.

The rod portion 142 moves in the front/rear direction (FWD arrowdirection and BWD arrow direction) with the piston portion 141 moving inthe front/rear direction. A seal member 143 is disposed at an endportion at the BWD arrow direction side of the cylinder portion 140. Theseal member 143 is arranged to prevent the oil, sealed in the inside ofthe cylinder portion 140, from leaking to the exterior. The rod portion142 may be arranged such that the rod portion 142 can move at a strokeof approximately 90 mm, for example, in the front/rear direction of thehull 2. The wire cable 11, which is connected to the bucket 10, isconnected to an end portion at the BWD arrow direction side of the rodportion 142, and the wire cable 11 is moved in the front/rear directionalong with the movement of the rod portion 142 in the front/reardirection.

A stroke sensor 144 is attached to the BWD arrow direction side of thecylinder portion 140. The stroke sensor 144 detects a stroke amount(drive amount) by which the rod portion 142 moves in the front/reardirection. That is, the stroke sensor 144 detects the stroke amount ofthe rod portion 142 to detect a movement amount of the bucket 10 that isconnected to the rod portion 142 via the wire cable 11. The strokesensor 144 is an example of a “detection unit” according to a preferredembodiment of the present invention.

The water jet propulsion watercraft 1 includes an oil flow apparatus 55that causes oil to flow between the cylinder portion 140 and the engine3. The oil flow apparatus 55 includes an oil passage 56, a solenoidvalve 16 provided in the oil passage 56, a regulator 18 provided in theoil passage 56, and the scavenge pump 35.

The oil passage 56 connects the inside of the engine 3 with the insideof the cylinder portion 140 of the hydraulic cylinder 14. The oilpassage 56 is arranged to cause the oil (lubricating oil) of the insideof the engine 3 to pass through as the oil (hydraulic oil) of thehydraulic cylinder 14. Specifically, the oil passage 56 includes aplurality of piping 15 a, 15 b, 17 a, 17 b, 19 a, and 19 b.

An upper end portion of the piping 15 a is connected to the front oilchamber 140 a. An upper end portion of the piping 15 b is connected tothe rear oil chamber 140 b.

The solenoid valve 16 is connected respectively to a lower end portionof the piping 15 a and a lower end portion of the piping 15 b. Thesolenoid valve 16 is an example of a “valve” according to a preferredembodiment of the present invention. The solenoid valve 16 is connectedto the scavenge pump 35 via the piping 17 b, the regulator 18, and thepiping 19 a.

The solenoid valve 16 is capable of switching among a first state ofallowing the oil delivered from the scavenge pump 35 to flow into thepiping 15 a, a second state of allowing the oil to flow into the piping15 b, and a third state of not allowing the oil to flow into either ofthe piping 15 a and 15 b. In the first state, the solenoid valve 16allows the oil to flow into the front oil chamber 140 a of the hydrauliccylinder 14. In the second state, the solenoid valve 16 allows the oilto flow into the rear oil chamber 140 b. In the third state, thesolenoid valve 16 does not allow the oil to flow into either of oilchambers 140 a and 140 b.

When the oil flows from the scavenge pump 35 into the front oil chamber140 a, the piston portion 141 is moved to the rear (BWD arrow direction)side. In this process, the piston portion 141 moves the wire cable 11rearward via the rod portion 142. The bucket 10 can consequently bemoved to the reverse drive position A.

On the other hand, when the oil flows from the scavenge pump 35 into therear oil chamber 140 b, the piston portion 141 is moved to the front(FWD arrow direction) side. In this process, the piston portion 141causes the wire cable 11 to move forward via the rod portion 142. Thebucket 10 can consequently be moved to the reverse drive position B (seeFIG. 3).

As is clear from FIG. 2 and FIG. 3, a portion of the rod portion 142that is housed inside the cylinder portion 140 is greater when thebucket 10 is at the forward drive position B than when the bucket 10 isat the reverse drive position A. That is, the hydraulic cylinder 14houses a greater portion of the rod portion 142 inside of the cylinderportion 140 during a forward drive operation. A time in which theforward drive operation is performed is markedly longer than a time inwhich a reverse drive operation is performed, and thus by the abovearrangement, the rod portion 142 can be protected effectively againstdust and other foreign matter.

The solenoid valve 16 is connected to the oil pan 32 a of the engine 3via the piping 17 a. The solenoid valve 16 is thereby arranged to becapable of returning the oil, delivered to the solenoid valve 16 by thescavenge pump 35, to the oil pan 32 a without letting the oil flow intothe hydraulic cylinder 14. When the bucket 10 is positioned at thereverse drive position A or the forward drive position B, the solenoidvalve 16 is arranged to return the oil from the scavenge pump 35 to theoil pan 32 a via the piping 17 a without letting the oil flow into thehydraulic cylinder 14. That is, the solenoid valve 16 is arranged so asnot to allow the oil to flow into either of the front oil chamber 140 aand the rear oil chamber 140 b of the hydraulic cylinder 14 when thebucket 10 is positioned at the reverse drive position A or the forwarddrive position B.

The regulator 18 is disposed at a downstream side of the scavenge pump35 and an upstream side of the hydraulic cylinder 14 in a direction offlow of the oil from the scavenger pump 35. The regulator 18 is arrangedto release the oil fed to the hydraulic cylinder 14 to the oil pan 32 a.The regulator 18 is an example of a “relief valve” according to apreferred embodiment of the present invention.

The regulator 18 is connected to the solenoid valve 16 via the piping 17b. Further, the regulator 18 is connected to the scavenge pump 35 viathe piping 19 a. Further, the regulator 18 is connected to the oil pan32 a via the piping 19 b.

The oil pan 32 a is provided below the regulator 18. When a pressure ofthe oil delivered from the scavenge pump 35 exceeds a predeterminedpressure (approximately 50 kPa, for example), the regulator 18 preventsthe exceeding oil pressure to within the predetermined pressure(approximately 50 kPa, for example). Specifically, the regulator 18 isarranged to return at least a portion of the oil via the piping 19 b tothe oil pan 32 a below the regulator 18 (lower portion of the engine 3)when the pressure of the oil delivered from the scavenge pump 35 exceedsthe predetermined pressure (approximately 50 kPa, for example). Theregulator 18 is arranged to deliver the oil at the pressure within thepredetermined pressure (approximately 50 kPa, for example) to thesolenoid valve 16 via the piping 17 b.

Thus, by driving the scavenge pump 35 arranged to recover the oil thathas lubricated the inside of the engine 3 to the oil pan 32 a, a portionof the oil that lubricates the inside of the engine 3 is arranged to besupplied to the hydraulic cylinder 14 through the oil passage 56.Consequently, there is no need to provide oil to be used just for movingthe bucket 10, a container for storing the oil, a pump for deliveringthe oil, etc.

Referring to FIG. 1, an ECU (engine control unit, also called anelectronic control unit) 38 is attached to an engine room 2 c sideportion of an upper portion of the bulkhead 2 d. The ECU 38 is anexample of a “control unit” according to a preferred embodiment of thepresent invention. The ECU 38 has a function of controlling the engine3, the solenoid valve 16, etc. The ECU 38 is electrically connected viawiring 39 to respective portions of the water jet propulsion watercraft1, such as a throttle valve (not shown), the stroke sensor 144, thesolenoid valve 16, the fuel tank 4, etc.

Referring to FIG. 4 and FIG. 5, a seat 21 for a rider to straddle, andfootrest portions 57 for a rider to place his/her feet, are provided atthe deck 2 a. The engine 3 and the hydraulic cylinder 14 are disposedbelow the seat 21. The seat 21 is attached to the deck 2 a and isdetachable from the deck 2 a. An opening 2 f arranged to be able toaccess to the engine room 2 c is provided below the seat 21. The opening2 f is closed by the seat 21.

The footrest portions 57 are disposed at a right side and a left side ofthe seat 21 and are positioned downward relative to a seat surface 58 ofthe seat 21. The footrest portions 57 are disposed to sandwich an upperportion of the engine 3 and the hydraulic cylinder 14 in the right/leftdirection.

A steering unit 22 arranged to steer the hull 2 is disposed in front ofthe seat 21. The steering unit 22 is an example of a “pair of steeringhandles” according to a preferred embodiment of the present invention.

FIG. 6 is a perspective view for describing an arrangement of a vicinityof the steering unit 22. The steering unit 22 includes a right grip 23and a left grip 24 that are held by the rider during steering. Anaccelerator lever 23 a is provided in a rotatable manner on the rightgrip 23. An accelerator position sensor 59 is disposed near theaccelerator lever 23 a and is arranged to detect an operation amount ofthe accelerator lever 23 a.

As shown in FIG. 1, a throttle wire 23 b is connected to the acceleratorlever 23 a of the right grip 23. The throttle wire 23 b is connected toan accelerator position sensor 59 provided in the interior of the hull2. The accelerator position sensor 59 has a function of detecting amovement amount of the throttle wire 23 b and transmits an electricalsignal based on the detected movement amount of the throttle wire 23 bto the ECU 38 via the wiring 39. The ECU 38 computes a rotational amountof an unillustrated throttle valve motor based on the transmittedelectrical signal and transmits a signal of the computed rotationalamount to an unillustrated throttle valve motor.

FIG. 7 is a perspective view for describing an arrangement around a leftgrip 24 of the steering unit 22. As shown in FIG. 6 and FIG. 7, a switchcase 26 arranged to have an outer peripheral surface of cylindricalshape is provided near a base portion of the left grip 24. A forwarddrive switch (F switch) 26 a that is operable by the rider is providedin the switch case 26. The forward drive switch (F switch) 26 a isprovided to move the bucket 10 to the forward drive position B in FIG.3.

A reverse drive switch (R switch) 26 b that is operable by the rider isprovided near the forward drive switch 26 a. The reverse drive switch (Rswitch) 26 b is provided to move the bucket 10 to the reverse driveposition A. Each of the forward drive switch 26 a and the reverse driveswitch 26 b is an example of a “switch” according to a preferredembodiment of the present invention.

FIG. 8 is a sectional view for describing a structure of the forwarddrive switch 26 a and the reverse drive switch 26 b. Each of the forwarddrive switch 26 a and the reverse drive switch 26 b has a button shapethat can be pressed by the rider. The wiring 39 is connected to each ofthe forward drive switch 26 a and the reverse drive switch 26 b.

As shown in FIG. 7, a bucket operation indication lamp portion 26 ccapable of displaying the position of the bucket 10 is provided to theleft of the forward drive switch 26 a and the reverse drive switch 26 b.The bucket operation indication lamp portion 26 c is an example of a“display unit” according to a preferred embodiment of the presentinvention.

The bucket operation indication lamp portion 26 c is provided in theswitch case 26 and is disposed at a position enabling visual recognitionby the rider.

FIG. 9 is a sectional view for describing a structure of the bucketoperation indication lamp portion 26 c. The bucket operation indicationlamp portion 26 c includes four LEDs 26 d, one LED 26 e that is largerthan the LEDs 26 d, an LED holder 26 f that holds the LEDs 26 d and 26e, and a protective plate 26 g. The protective plate 26 g is formed of alight transmitting material and is arranged to protect the LEDs 26 d and26 e while enabling light from the LEDs 26 d and 26 e to be visuallyrecognized from the exterior.

As shown in FIG. 7, one LED 26 d among the four LEDs 26 d is disposedadjacent the forward drive switch 26 a. The remaining three LEDs 26 dand the LED 26 e are disposed at substantially equal intervals along acircumferential direction of the switch case 26 arranged to have theouter peripheral surface of cylindrical shape.

The one LED 26 e that is larger than the LEDs 26 d is positionedadjacent the reverse drive switch 26 b. The LEDs 26 d and 26 e arerespectively arranged to be lit (to optically indicate) incorrespondence to the position of the bucket 10 (see FIG. 2) during itsmovement between the reverse drive position A and the forward driveposition B.

Referring to FIG. 7, a notification lamp portion 26 h is provided in theswitch case 26. The notification lamp portion 26 h is disposed betweenthe forward drive switch 26 a and the reverse drive switch 26 b. Thenotification lamp portion 26 h is arranged to be lit when the forwarddrive switch 26 a or the reverse drive switch 26 b is operated by therider when the rotational speed of the engine 3 is not less than apredetermined value (approximately 1250 rpm, for example). That themovement of the bucket 10 is not performed is thereby notified to therider.

FIG. 10 is a sectional view for describing a structure of thenotification lamp portion 26 h. The notification lamp portion 26 hincludes an LED 26 i, an LED holder 26 j that holds the LED 26 i, and aprotective plate 26 k that protects the LED 26 i. The LED 26 i isconnected to the wiring 39 and the wiring 39 is connected to the ECU 38(see FIG. 1).

The notification lamp portion 26 h is arranged to be lit if the bucket10 is positioned at the reverse drive position A during starting of theengine 3. Thus, if during starting of the engine 3, the bucket 10 ispositioned at the reverse drive position A, the rider can check the litnotification lamp portion 26 h. The rider can thereby confirm that thehull 2 starts moving in reverse when the accelerator is opened.

As shown in FIG. 1, a speaker 28 is preferably provided below thesteering unit 22. The speaker 28 is arranged to generate a sound tonotify to the rider that the bucket 10 is not moved. The speaker 28 isconnected to the ECU 38 via the wiring 39. The speaker 28 generates thesound when the rider operates the forward drive switch 26 a or thereverse drive switch 26 b (see FIG. 7) when the rotational speed of theengine 3 is not less than the predetermined value (approximately 1250rpm, for example). That the movement of the bucket 10 is not performedis thereby notified to the rider.

FIG. 11 is a perspective view of an arrangement of a deceleration aidlever 27. The deceleration aid lever 27 is provided at a FWD arrowdirection side portion of the switch case 26. The deceleration aid lever27 is an example of the “switch” according to a preferred embodiment ofthe present invention. The deceleration aid lever 27 is disposed infront of the left grip 24 and protrudes to the left from the switch case26. The deceleration aid lever 27 is arranged to be operable by therider when he/she wishes to decelerate the water jet propulsionwatercraft 1.

The deceleration aid lever 27 is urged by an unillustrated spring in adirection of separating from the left grip 24 (FWD arrow direction). Thedeceleration aid lever 27 is arranged so that the deceleration lever 27is positioned at a position E when the deceleration lever 27 is notoperated. The deceleration aid lever 27 is arranged to be capable ofbeing drawn to a position F when operated by the rider (duringdecelerating). In this case, the deceleration aid lever 27 turns ON adeceleration aid switch 60 disposed near a base of the deceleration aidlever 27 inside of the switch case 26. A signal that causes the bucket10 to move to the reverse drive position A is thereby arranged to betransmitted to the ECU 38.

FIG. 12 is a block diagram for describing an electrical arrangementrelated to the ECU 38. The water jet propulsion watercraft 1 is providedwith a rotational speed sensor 61, a throttle valve motor 62, and thewiring 39 that electrically connects the ECU 38 and respective portions.

The rotational speed sensor 61 detects the rotational speed of theengine 3. The rotational speed sensor 61 is an example of a “rotationalspeed detection unit” according to a preferred embodiment of the presentinvention. The rotational speed sensor 61 is connected to the ECU 38. Arotational speed detection signal of the engine 3 that is output by therotational speed sensor 61 is input into the ECU 38.

The throttle valve motor 62 is provided for opening and closingoperations of the throttle valve (not shown) of the engine 3. Therotational speed of the engine 3 (load of the engine 3) is controlled bythe opening and closing operations of the throttle valve by the throttlevalve motor 62. The throttle valve motor 62 is connected to the ECU 38.The opening degree of the throttle valve is controlled by the ECU 38which controls a rotational angle of the throttle valve motor 62.

The accelerator position sensor 59 is connected to the ECU 38. Adetection signal of the operation amount of the accelerator lever 23 aoutput by the accelerator position sensor 59 is input into the ECU 38.

The stroke sensor 144 is connected to the ECU 38. A position detectionsignal of the rod portion 142 of the hydraulic cylinder 14 output by thestroke sensor 144 is input into the ECU 38.

The solenoid valve 16 is connected to the ECU 38, and the ECU 38controls the operation of the solenoid valve 16.

The deceleration aid switch 60 is connected to the ECU 38. When thedeceleration aid switch 60 is turned ON by operation of the decelerationaid lever 27, a signal is input from the deceleration aid switch 60 intothe ECU 38.

The forward drive switch 26 a and the reverse drive switch 26 b arerespectively connected to the ECU 38. When each of the forward driveswitch 26 a and the reverse drive switch 26 b is operated, a signal fromthe corresponding forward drive switch 26 a or reverse drive switch 26 bis input into the ECU 38.

The LEDs 26 d and 26 e, the LED 26 i of the notification lamp portion 26h, and the speaker 28 are respectively connected to the ECU 38. The ECU38 respectively controls the LEDs 26 d and 26 e, the LED 26 i of thenotification lamp portion 26 h, and the speaker 28.

Operations performed when the bucket 10 is moved shall now be describedin detail. First, the operations performed when the bucket 10 is movedfrom the forward drive position B to the reverse drive position A shallbe described.

FIG. 13 is a flowchart for describing control for causing the bucket 10move from the forward drive position B to the reverse drive position Aby the ECU 38.

When the rider operates the reverse drive switch 26 b or thedeceleration aid lever 27 in the state where the bucket 10 is positionedat the forward drive position B (step S1: YES), the ECU 38 determineswhether the rotational speed of the engine 3 is less than thepredetermined value or not less than the predetermined value (step S2).

If the rotational speed of the engine 3 is not less than thepredetermined value (step S2: not less than predetermined value), theECU 38 lights up the LED 26 i of the notification lamp portion 26 h andcauses the speaker 28 to generate sound (step S3). That the bucket 10 isnot displaced from the forward drive position B is thereby notified tothe rider.

The rotational speed of the engine 3 is then controlled to a lowrotational speed less than the predetermined value (step S4). Forexample, the ECU 38 controls the throttle valve motor 62 to close thethrottle valve and reduce the rotational speed of the engine 3.

The ECU 38 waits while the rotational speed of the engine 3 is not lessthan the predetermined value (step S5: not less than predeterminedvalue). When the rotational speed of the engine 3 becomes less than thepredetermined value (step S5: less than predetermined value), the ECU 38turns off the LED 26 i of the notification lamp portion 26 h and stopsthe generation of sound by the speaker 28 (step S6).

After the LED-OFF and sound-OFF control in step S6 or after it has beenjudged in step S2 that the rotational speed of the engine 3 is less thanthe predetermined value, the ECU 38 performs a control of displacing thebucket 10 from the forward drive position B to the reverse driveposition A (step S7).

Specifically, with reference to FIG. 2 and FIG. 13, the ECU 38 controlsthe solenoid valve 16 to cause the oil to flow from the scavenge pump 35into the front oil chamber 140 a of the cylinder portion 140 of thehydraulic cylinder 14. In this process, the oil flowing out from therear oil chamber 140 b is returned to the oil pan 32 a.

More specifically, the ECU 38 controls the solenoid valve 16 to switchthe path of the oil delivered from the scavenge pump 35 and via theregulator 18. That is, switching is performed from a state where the oilis returned to the oil pan 32 a from the piping 17 a to a state wherethe oil flows into the front oil chamber 140 a of the cylinder portion140 via the piping 15 a.

With the inflow of the oil into the front oil chamber 140 a, the pistonportion 141 is moved in the BWD arrow direction. The oil is therebyreturned from the rear oil chamber 140 b to the solenoid valve 16 viathe piping 15 b. The oil that is returned to the solenoid valve 16 isreturned to the oil pan 32 a via the piping 17 a.

With the movement of the piston portion 141 in the BWD arrow direction,the rod portion 142 is moved in the BWD arrow direction. The wire cable11 is thereby moved in the BWD arrow direction. With the movement of thewire cable 11 in the BWD arrow direction, the bucket 10 is rotated so asto be positioned to the rear of the deflector 9 and the bucket 10 isthereby moved to the reverse drive position A.

Based on the position of the rod portion 142 detected by the strokesensor 144 at this time, the ECU 38 determines the position of thebucket 10 and performs control of lighting up the LEDs 26 d according tothe position of the bucket 10 (step S8). While the bucket 10 is beingdisplaced, the ECU 38 lights up just a corresponding number of the LEDs26 d, and when the bucket 10 reaches the reverse drive position A, theECU 38 lights up the LED 26 e adjacent to the reverse drive switch 26 b.

Based on the position of the rod portion 142 detected by the strokesensor 144 at this time, the ECU 38 determines whether or not the bucket10 has reached the reverse drive position A (step S9). When the bucket10 reaches the reverse drive position A (step S9: YES), the ECU 38cancels the low rotation speed control of the engine 3 (step S10) andreturns to ordinary throttle control. Specifically, a state where theECU 38 controls the throttle valve motor 62 is entered so that thethrottle valve opens and closes according to the operation amount of thethrottle lever 23 a.

As a result of the above-described control, when the water flow jettedfrom the deflector 9 is strong, movement of the bucket 10 against theforce of this water flow can be prevented. An excessive load can therebybe prevented from acting on and breaking the bucket 10 and the hydrauliccylinder 14.

For example, if decelerating of the water jet propulsion watercraft 1 isdesired, the rider grips the deceleration aid lever 27 (see FIG. 6)while gripping the accelerator lever 23 a. In this case, the rotationalspeed of the engine 3 decreases while the bucket 10 moves from theforward drive position B to the reverse drive position A. The bucket 10is thus moved smoothly to the reverse drive position A. When the bucket10 completes the movement to the reverse drive position A, therotational speed of the engine 3 increases immediately and a frontwardjet flow is generated. The water jet propulsion watercraft 1 can therebybe decelerated.

The operations performed when the bucket 10 is moved from the reversedrive position A to the forward drive position B shall now be described.

FIG. 14 is a flowchart for describing control for causing the bucket 10to move from the reverse drive position A to the forward drive positionB by the ECU 38.

When the rider presses the forward drive switch 26 a in the state wherethe bucket 10 is positioned at the reverse drive position A (step R1:YES), the ECU 38 determines whether the rotational speed of the engine 3is less than the predetermined value or not less than the predeterminedvalue (step R2). If the rotational speed of the engine 3 is not lessthan the predetermined value (step R2: not less than predeterminedvalue), the ECU 38 lights up the LED 26 i of the notification lampportion 26 h and causes the speaker 28 to generate sound (step R3). Thatthe bucket 10 is not displaced from the reverse drive position A isthereby notified to the rider.

At the same time, the ECU 38 controls the rotational speed of the engine3 to a low rotational speed less than the predetermined value (step R4).The ECU 38, for example, controls the throttle valve motor 62 to closethe throttle valve and reduce the rotational speed of the engine 3.

The ECU 38 waits while the rotational speed of the engine 3 is not lessthan the predetermined value (step R5: not less than predeterminedvalue). When the rotational speed of the engine 3 becomes less than thepredetermined value (step R5: less than predetermined value), the ECU 38turns off the LED 26 i of the notification lamp portion 26 h and stopsthe generation of sound by the speaker 28 (step R6).

After the LED-OFF and sound-OFF control in step R6 or after it has beenjudged in step R2 that the rotational speed of the engine 3 is less thanthe predetermined value, the ECU 38 performs a control of displacing thebucket 10 from the reverse drive position A to the forward driveposition B (step R7).

Specifically, with reference to FIG. 13 and FIG. 14, the ECU 38 controlsthe solenoid valve 16 to cause the oil to flow from the scavenge pump 35into the rear oil chamber 140 b of the cylinder portion 140 of thehydraulic cylinder 14. In this process, the oil flowing out from thefront oil chamber 140 a is returned to the oil pan 32 a.

More specifically, the ECU 38 controls the solenoid valve 16 to switchthe path of the oil. Switching is thereby performed from a state wherethe oil, delivered from the scavenge pump 35 and via the regulator 18,is returned to the oil pan 32 a from the piping 17 a to a state wherethe oil flows into the rear oil chamber 140 b of the cylinder portion140 via the piping 15 b. The oil thereby flows into the rear oil chamber140 b.

With the inflow of the oil into the rear oil chamber 140 b, the pistonportion 141 is moved in the FWD arrow direction. The oil is therebyreturned from the front oil chamber 140 a to the solenoid valve 16 viathe piping 15 a. The oil that is returned to the solenoid valve 16 isreturned to the oil pan 32 a via the piping 17 a.

With the movement of the piston portion 141 in the FWD arrow direction,the rod portion 142 is moved in the FWD arrow direction. The wire cable11 is thereby moved in the FWD arrow direction. With the movement of thewire cable 11 in the FWD arrow direction, the bucket 10 is rotated so asto be positioned above the deflector 9 and the bucket 10 is therebymoved to the forward drive position B.

Based on the position of the rod portion 142 detected by the strokesensor 144 at this time, the ECU 38 determines the position of thebucket 10 and performs control of lighting up the LEDs 26 d according tothe position of the bucket 10 (step R8). While the bucket 10 is beingdisplaced, the ECU 38 turns off the LED 26 e adjacent to the reversedrive switch 26 b and lights up just a corresponding number of the LEDs26 d. When the bucket 10 reaches the forward drive position B, the ECU38 lights up the single LED 26 d adjacent to the forward drive switch 26a.

Based on the position of the rod portion 142 detected by the strokesensor 144, the ECU 38 determines whether or not the bucket 10 hasreached the forward drive position B (step R9). When the bucket 10reaches the forward drive position B (step R9: YES), the ECU 38 cancelsthe low rotation speed control of the engine 3 (step R10) and moves toordinary throttle control. Specifically, the state where the ECU 38controls the throttle valve motor 62 is entered so that the throttlevalve opens and closes according to the operation amount of the throttlelever 23 a.

As described above, in the first preferred embodiment of the presentinvention, the hydraulic cylinder 14 is provided in the interior of thehull 2. The hydraulic cylinder 14 can thus be prevented from constantlycontacting water directly. Adhesion of rust and other foreign matter onvarious components of the hydraulic cylinder 14 can thereby beprevented. Damaging of various portions of the hydraulic cylinder 14 dueto the foreign matter during driving of the hydraulic cylinder 14 canthereby be prevented.

The oil passage 56 is provided. The oil of the inside of the engine 3 isthus supplied to the hydraulic cylinder 14 via the oil passage 56 andused as the hydraulic oil of the hydraulic cylinder 14. A lubricatingoil supply system of the inside of the engine 3 and a hydraulic oilsupply system for the hydraulic cylinder 14 are thus combined. Thelubricating oil supply system and the hydraulic oil supply system canthus be arranged using an apparatus in common (the scavenge pump 35).

The number of components inside the hull 2 can thus be made small.Installation space restrictions are severe with the water jet propulsionwatercraft 1 because, in addition to the space inside the hull 2 beingsmall, a space partitioned from the exterior so that water does notenter inside the hull 2 (engine room 2 c) must be formed. Even in theinterior of the hull 2 with such severe installation space restrictions,the hydraulic oil supply system that is low in the number of componentsand is thus space-saving can be installed along with the hydrauliccylinder 14.

For example, with a water jet propulsion watercraft in which thelubricating oil supply system and the hydraulic oil supply system areformed separately, an oil pump, etc., must be provided in each of thesesystems. The number of components to be housed inside the hull thusbecomes large. As mentioned above, installation space restrictions aresevere in the water jet propulsion watercraft. An increase in the numberof components causes an increase of installation space and consequently,it becomes impossible to install an independent hydraulic oil supplysystem together with the hydraulic cylinder 14 for bucket drive insidethe hull 2.

In the present arrangement, the inside of the engine 3 communicates withthe inside of the hydraulic cylinder 14 via the oil passage 56, and theoil that lubricates the inside of the engine 3 is also used as thehydraulic oil of the hydraulic cylinder 14. Thus, by exchanging the usedlubricating oil inside of the engine 3 with new lubricating oil, thehydraulic oil of the hydraulic cylinder 14 can be exchanged at the sametime. Specialized work for exchanging the hydraulic oil inside thehydraulic cylinder 14 is thus made unnecessary and the work ofexchanging the oil inside the hydraulic cylinder 14 can practically beomitted. The trouble of performing maintenance on the water jetpropulsion watercraft 1 can thus be lessened.

As described above, by the arrangement of using the oil for lubricationof the inside of the engine 3 in common as the hydraulic oil of thehydraulic cylinder 14, the hydraulic cylinder 14 and the hydraulic oilsupply system therefore can be housed in the narrow space inside thehull 2 and facilitation of maintenance can be achieved at the same time.

As described above, in the first preferred embodiment of the presentinvention, the wire cable 11 that transmits the driving force of thehydraulic cylinder 14 to the bucket 10 is preferably provided. Thedriving force of the hydraulic cylinder 14 disposed in the interior ofthe hull 2 can thereby be transmitted via the wire cable 11 to thebucket 10 at the exterior of the hull 2.

As described above, in the first preferred embodiment of the presentinvention, the rod portion 142 of the hydraulic cylinder 14 ispreferably disposed to move in the substantially front/rear direction ofthe hull 2. The rod portion 142 is thereby disposed to move in thesubstantially front/rear direction that is perpendicular orsubstantially perpendicular to the up/down direction, which is avibration direction of the hull 2. Changing of the position of the rodportion 142 in synchronization with vibration in the up/down directionof the hull 2 can thereby be prevented. The engine 3 is disposed alongthe front/rear direction of the hull 2, and the elongate cylinderportion 140 can thus be disposed so as to be parallel or substantiallyparallel to the engine 3 in the right/left direction. The hydrauliccylinder 14 can thereby be positioned near the engine 3, thus effectiveuse can be made of the space inside the hull 2. The hull 2 (lateralwidth of the space inside the hull 2) can thereby be made more compact.In other words, the hydraulic cylinder 14 can be housed in the limitedspace inside the compact hull 2. Further, the wire cable 11 connected tothe rod portion 142 is disposed inside the hull 2 without being bent tothe right or left. The wire cable 11 can thus move smoothly and movementof the bucket 10 can be performed much more smoothly.

As described above, in the first preferred embodiment of the presentinvention, the scavenge pump 35 is preferably arranged to feed the oilto the hydraulic cylinder 14. The need to provide a separate oil pumpjust for supplying the oil to the hydraulic cylinder 14 is eliminatedand the number of components is decreased accordingly. The scavenge pump35 is arranged to be driven with the rotation of the crankshaft 31. Thescavenge pump 35 can thereby be driven using the driving force of theengine 3.

As described above, in the first preferred embodiment of the presentinvention, the regulator 18 is preferably provided for releasing the oilfed to the hydraulic cylinder 14 by the scavenge pump 35 to the oil pan32 a. The regulator 18 can be actuated when the discharge pressure ofthe scavenge pump 35 increases with the increase of the rotational speedof the engine 3. The oil from the scavenge pump 35 can thereby bereleased to the oil pan 32 a. Consequently, a pressure of the oil fed tothe hydraulic cylinder 14 can be prevented from becoming excessivelyhigh.

As described above, in the first preferred embodiment of the presentinvention, the oil pan 32 a is preferably provided at the lower portionof the engine 3 below the regulator 18. The excess oil released by theregulator 18 can thereby be returned to the oil pan 32 a below theregulator 18 by use of gravity.

In the first preferred embodiment of the present invention, the feedpump 34 and the scavenge pump 35 are preferably provided as the oilpumps of the engine 3. The scavenge pump 35 is arranged to recover theoil inside the engine 3 into the oil pan 32 a and its lubricating oildischarge pressure may be low because it suffices that the scavenge pump35 be able to suck in the oil. On the other hand, the feed pump 34 needsto pump the oil inside of the engine 3 and thus its oil dischargepressure needs to be high. Thus, in regard to the oil dischargepressure, that of the scavenge pump 35 may be lower than that of thefeed pump 34. By being arranged to feed the oil into the hydrauliccylinder 14 by the scavenge pump 35, feeding of the oil into hydrauliccylinder 14 at an excessive high pressure can be prevented.

In the first preferred embodiment of the present invention, the drivedirection of the piston portion 141 of the hydraulic cylinder 14 ispreferably arranged to be changed in response to the operation of theforward drive switch 26 a and the reverse drive switch 26 b. The ridercan easily move the bucket 10 to the forward drive position B or thereverse drive position A by operating the forward drive switch 26 a orthe reverse drive switch 26 b. For example, by operating the reversedrive switch 26 b during moving forward of the water jet propulsionwatercraft 1, the bucket 10 can be positioned at the reverse driveposition A. The bucket 10 can thereby used as a deceleration aidapparatus of the water jet propulsion watercraft 1.

As described above, in the first preferred embodiment of the presentinvention, when the rotational speed of the engine 3 is not less thanthe predetermined value (approximately 1250 rpm, for example) and therider operates the forward drive switch 26 a or the reverse drive switch26 b, the ECU 38 preferably lowers the rotational speed of the engine 3to less than the predetermined value and thereafter changes the drivedirection of the piston portion 141. Movement of the bucket 10 againstthe force of the water flow jetted from the deflector 9 can thereby beavoided when the rotational speed of the engine 3 is not less than thepredetermined value and the water flow is thus strong.

In this case, the bucket 10 is moved after the rotational speed of theengine 3 is decreased to less than the predetermined value and the waterflow jetted from the deflector 9 is weakened. The water flow jetted fromthe deflector 9 can thus be prevented from applying an excessive load tothe bucket 10 and the hydraulic cylinder 14 that drives the bucket 10.Consequently, breakage of the bucket 10 and the hydraulic cylinder 14can be prevented.

For example, that the engine rotational speed is not more than thepredetermined value is made a condition for moving the bucket 10 fromthe forward drive position B to the reverse drive position A duringmoving forward of the water jet propulsion watercraft 1. Breakage of thebucket 10 and the hydraulic cylinder 14 can thereby be prevented forexample when using the bucket 10 as the deceleration aid apparatus ofthe water jet propulsion watercraft 1.

When the rotational speed of the engine 3 is low, the rotational speedsof the respective rotating portions, such as the crankshaft 31, cam,etc., inside the engine 3 are low and it thus suffices for the oilsupplied to these rotating portions to be low in amount or pressure. Aportion of the oil inside the engine 3 is thus arranged to be suppliedto the hydraulic cylinder 14 when it suffices for the supply amount ofthe lubricating oil supplied to the respective portions inside theengine 3 to be low. The oil inside the engine 3 can thus be supplied tothe hydraulic cylinder 14 without placing a burden on the respectiveportions inside the engine 3. The lubricating oil can thereby be usedfor driving of the hydraulic cylinder 14 without lowering durability ofthe engine 3.

As described above, in the first preferred embodiment of the presentinvention, the ECU 38 preferably controls the solenoid valve 16 to stopthe flow of oil into the hydraulic cylinder 14 when the bucket 10 ispositioned at the forward drive position B or the reverse drive positionA. The hydraulic cylinder 14 can thereby be prevented from generating anexcessive driving force when the bucket 10 is positioned at the reversedrive position A or the forward drive position B and there is no need tomove the bucket 10.

As described above, in the first preferred embodiment of the presentinvention, the hydraulic cylinder 14 preferably is disposed near theportion in the interior of the hull 2 at which the engine 3 is disposed(near the head cover 54). The oil passage 56 can thereby be made short.The space occupied by the oil passage 56 inside the hull 2 can therebybe lessened. By lessening the space occupied by the oil passage 56 inthe water jet propulsion watercraft 1 with which the interior of thehull 2 is narrow, a degree of freedom of design of positioning ofcomponents inside the hull 2 can be increased.

As described above, in the first preferred embodiment of the presentinvention, the hydraulic cylinder 14 is preferably supported by theengine 3. The oil passage 56 can thereby be disposed close to the engine3 and the oil passage 56 can be made shorter. Further, the oil passage56 can be disposed near the engine 3 and effective use can thus be madeof the space inside the hull 2.

As described above, in the first preferred embodiment of the presentinvention, the hydraulic cylinder 14 is preferably disposed at the innerside relative to both ends of the engine 3 in the width direction of theengine 3 in plan view. The engine 3 and the hydraulic cylinder 14 canthereby be prevented from becoming large as a whole in the widthdirection of the engine 3 (right/left direction). Especially in thestraddle type, small-scale water jet propulsion watercraft 1, the seat21 is disposed above the engine 3 and the footrest portions 57 for therider are disposed at both right and left sides of the engine 3. Thus,if the engine 3 and other apparatuses disposed below the seat 21 arelarge in the width direction of the engine 3, width of the seat 21becomes large. When the width of the seat 21 is large, it is not easyfor a relatively small rider to straddle the seat 21. In such a straddletype water jet propulsion watercraft 1, to suppress the width of theseat 21 brings an advantage to facilitate boarding and exiting of thewater jet propulsion watercraft 1.

As described above, in the first preferred embodiment of the presentinvention, the cylinder portion 140 of the hydraulic cylinder 14 ispreferably supported by the upper portion (head cover 54) of the engine3. The hydraulic cylinder 14 can thereby be positioned by making use ofthe space above the engine 3 and the support structure can be maderobust. Further, maintainability of the hydraulic cylinder 14 can beimproved because the hydraulic cylinder 14 can be touched readily fromabove the hull 2. Even if water happens to enter inside the hull 2,immersion of the hydraulic cylinder 14 in water can be prevented.

As described above, in the first preferred embodiment of the presentinvention, the direction in which the wire cable 11 is pushed and pulledby the hydraulic cylinder 14 preferably is substantially parallel to theaxial direction of the cylinder portion 140 of the hydraulic cylinder14. According to this arrangement, the wire cable 11 can be disposedsubstantially parallel to the axial direction of the cylinder portion140. The wire cable 11 can thereby be disposed compactly inside the hull2.

The wire cable 11 is disposed along the front/rear direction of the hull2, and the space occupied in the right/left direction by the wire cable11 inside the hull 2 can thus be reduced.

As described above, in the first preferred embodiment of the presentinvention, the hydraulic cylinder 14 preferably is disposed below theseat 21. This arrangement can be applied advantageously to the straddletype, small-scale water jet propulsion watercraft 1. With the jetpropulsion watercraft 1, the space inside the hull 2 is the narrow spacebelow the seat 21. The installation space for the hydraulic cylinder 14is thus extremely limited. The hydraulic oil supply system that makesuse of the lubricating oil supply system for the engine 3 can bedisposed along with the hydraulic cylinder 14 in the limited space. Itthereby becomes possible to install the hydraulic cylinder 14 fordriving the bucket 10 inside the hull 2 in the saddle type, small-scalewater jet propulsion watercraft 1.

As described above, in the first preferred embodiment of the presentinvention, the hydraulic cylinder 14 preferably is disposed upwardrelative to the lower end portion of the air ventilation hose 5.According to this arrangement, when water enters from the airventilation hose 5, the water drops below from the lower end portion ofthe air ventilation hose 5. Consequently, water that has entered intothe hull 2 from the air ventilation hose 5 can be prevented fromadhering onto the hydraulic cylinder 14.

As described above, in the first preferred embodiment of the presentinvention, the drive amount of driving by the piston portion 141 of thehydraulic cylinder 14 preferably is detected by the stroke sensor 144.The ECU 38 can thereby readily determine the position of the bucket 10based on the detected drive amount of the piston portion 144.

As described above, the first preferred embodiment of the presentinvention is preferably provided with the spring member 12 for holdingthe bucket 10 at the forward drive position B. The bucket 10 can be heldat the forward drive position B by the spring member 12. The bucket 10can be held at the forward drive position by the spring member 12 evenin the case where the oil is not made to flow into the hydrauliccylinder 14 after the bucket 10 has been moved to the forward driveposition B.

As described above, in the first preferred embodiment of the presentinvention, the portion of the rod portion 141 of the hydraulic cylinder14 housed inside the cylinder portion 140 when the bucket 10 is at theforward drive position B preferably is greater than that when the bucket10 is at the reverse drive position A. Ordinarily, the bucket 10 ispositioned at the forward drive position B for a longer time than at thereverse drive position A. The time during which the greater portion ofthe rod portion 141 is housed in the cylinder portion 140 can thus bemade long and adhesion of dust and other foreign matter on the rodportion 141 can be reliably prevented.

Second Preferred Embodiment

A structure of a water jet propulsion watercraft 200 according to asecond preferred embodiment of the present invention shall now bedescribed. Each of FIG. 15 and FIG. 16 is a sectional view of an overallarrangement of the water jet propulsion watercraft 200 according to thesecond preferred embodiment of the present invention.

Referring to FIG. 15, in the second preferred embodiment of the presentinvention, a hydraulic cylinder 214 is disposed at a rear (BWD arrowdirection) side relative to the bulkhead 2 d. An example where a forwarddrive switch 226 a and a reverse drive switch 226 b are disposed betweena steering unit 222 and the seat 21 shall be described.

The engine 203 includes a crankshaft 231 and a crankcase 232. The engine203 is disposed so that the crankshaft 231 extends in the front/reardirection (FWD arrow direction and BWD arrow direction). The crankcase232 rotatably holds the crankshaft 231. An oil pan 232 a, storing oilthat lubricates an inside of the engine 203, is provided at a lowerportion of the crankcase 232 (engine 203). The oil pan 232 a is anexample of the “oil storage portion” according to a preferred embodimentof the present invention.

The engine 203 is provided with a scavenge pump 235. The scavenge pump235 sucks in the oil, which has lubricated respective portions of theengine 203, to recover the oil, which has lubricated the inside of theengine 203, into the oil pan 232 a. The scavenge pump 235 is an exampleof the “oil pump” and the “second oil pump” according to a preferredembodiment of the present invention.

A rotation shaft of the scavenge pump 235 is connected to the crankshaft231 and is arranged to be driven integrally with the crankshaft 231 withthe rotation of the crankshaft 231.

A wire cable 211 is connected to the upper side portion of the bucket10. The wire cable 211 is an example of the “cable” according to apreferred embodiment of the present invention. The wire cable 211extends to the outer side of the hull 2 from the interior of the hull 2.The wire cable 211 connects the hydraulic cylinder 214 and the bucket 10via a link mechanism 245. That is, the wire cable 211 connects thehydraulic cylinder 214 at the inner side of the hull 2 and the bucket 10disposed at the outer side of the hull 2. A driving force of thehydraulic cylinder 214 is thereby transmitted to the bucket 10.

With the wire cable 211 being moved in the front/rear direction by thehydraulic cylinder 214 and the link mechanism 245, the bucket 10 rotates(moves) between a reverse drive position C at the rear of the deflector9 and a forward drive position D (see FIG. 16). The bucket 10 at theforward drive position D is disposed above the deflector 9.

When the bucket 10 is positioned at the reverse drive position C asshown in FIG. 15, water is jetted rearward toward the bucket 10 from thedeflector 9. The water that is jetted rearward hits the bucket 10 and isconverted forward. A propulsive force that propels the hull 2 rearwardis thereby applied to the hull 2.

On the other hand, when the bucket 10 is positioned at the forward driveposition D as shown in FIG. 16, the water jetted rearward from thedeflector 9 is jetted rearward without hitting the bucket 10. Apropulsive force that propels the hull 2 forward is thereby applied tothe hull 2.

The hydraulic cylinder 214 is disposed at a rear portion of the interiorof the hull 2. The hydraulic cylinder 214 is disposed at the rearrelative to the bulkhead 2 d. That is, the hydraulic cylinder 214 isdisposed at the rear relative to the engine 3. Further, hydrauliccylinder 214 is disposed upward relative to the lower end portion 5 a ofthe air ventilation hose 5.

The hydraulic cylinder 214 includes a cylinder portion 240, a pistonportion 241 sliding along an inner wall of the cylinder portion 240, anda rod portion 242 connected to the piston portion 241.

An inside of the cylinder portion 240 includes a front oil chamber 240 awhich is a FWD arrow direction side portion partitioned by the pistonportion 241, and a rear oil chamber 240 a which is a BWD arrow directionside portion.

The piston portion 241 is disposed to move in a substantially front/reardirection. The rod portion 242 is thereby enabled to move in asubstantially front/rear direction.

A seal member 243 is disposed at an end portion at the FWD arrowdirection side of the cylinder portion 240. The seal member 243 isarranged to prevent the oil, sealed in the inside of the cylinderportion 240, from leaking to the exterior. The rod portion 242 extendstoward the FWD arrow direction in the state of being sealed by the sealmember 243.

An upper end side of the link mechanism 245 is connected to an endportion at the FWD arrow direction side of the rod portion 242. The wirecable 211 is connected to a lower end side of the link mechanism 245.

The link mechanism 245 has a function of moving the wire cable 211 in adirection opposite a movement direction of the rod portion 242. The linkmechanism 245 causes the wire cable 211 stroke to be larger than astroke (movement amount in the front/rear direction) of the rod portion242. The cable 211 is thereby made to undergo an adequate stroke to movethe bucket 10. Further, as is clear from FIG. 15 and FIG. 16, a portionof the rod portion 242 of the hydraulic cylinder 214 that is housed inthe cylinder portion 240 is arranged to be greater when the bucket 10 isat the forward drive position D than when the bucket 10 is at thereverse drive position C.

FIG. 17 is a perspective view for describing an arrangement of the linkmechanism 245. The link mechanism 245 includes a rod engaging portion245 a arranged to slidably engage with the rod portion 242, a wireengaging portion 245 b arranged to engage with the wire cable 211, and asupporting point portion 245 c which is a center of rotation of the linkmechanism 245. The rod engaging portion 245 a and the wire engagingportion 245 b are arranged integrally and oppose each other across thesupporting point portion 245 c.

A length L1 between an upper end portion of the rod engaging portion 245a and the supporting point portion 245 c is shorter than a length L2between the wire engaging portion 245 b and the supporting point portion245 c (L1<L2). That is, when the link mechanism 245 is rotated about thesupporting point portion 245 c, a movement distance L3 in the front/reardirection of the wire engaging portion 245 b is greater than a movementdistance L4 in the front/rear direction of the rod engaging portion 245a (L3>L4). The movement amount of the rod 242 can thereby be made smalland the movement amount of the cable 211 can be made adequately long.The front/rear length of the hydraulic cylinder 214 can thus beshortened, and the hydraulic cylinder 214 can thus be disposed morereadily in a narrow space to the rear of the bulkhead 2 d. As a resultof reduction of the stroke amount of the piston portion 241, a forcenecessary for causing the piston portion 241 stroke is increased. Theforce necessary to cause the piston portion 241 stroke can be secured bybeing arranged to make large the diameter of the piston portion 241 ofthe hydraulic cylinder 214.

Referring to FIG. 15, the link mechanism 245 is arranged so that thewire cable 211 is moved rearward when the rod portion 242 is movedforward. That is, unlike in the first preferred embodiment of thepresent invention, the bucket 10 that is connected to the wire cable 211is arranged to be moved to the reverse drive position C with themovement of the rod portion 242 in the FWD arrow direction.

Further, the link mechanism 245 is arranged so that the wire cable 211is moved forward when the rod portion 242 is moved rearward. That is,the bucket 10 that is connected to the wire cable 211 is arranged to bemoved to the forward drive position D with the movement of the rodportion 242 in the BWD arrow direction.

A stroke sensor 244 is attached to the FWD arrow direction side of thecylinder portion 240. The stroke sensor 244 detects the stroke amount(drive amount) of the rod portion 242 with respect to the front/reardirection. The stroke sensor 244 is an example of the “detection unit”according to a preferred embodiment of the present invention.

The water jet propulsion watercraft 200 includes an oil flow apparatus255 that causes oil to flow between the cylinder portion 240 and theengine 203.

The oil flow apparatus 255 includes an oil passage 256, a solenoid valve216 provided in the oil passage 256, a regulator 218 provided in the oilpassage 256, and the scavenge pump 235.

The oil passage 256 connects the inside of the engine 203 with theinside of the cylinder portion 240 of the hydraulic cylinder 214. Theoil passage 256 is arranged to allow the oil (lubricating oil) inside ofthe engine 203 to pass through as the oil (hydraulic oil) of thehydraulic cylinder 214. Specifically, the oil passage 256 includes aplurality of piping 215 a, 215 b, 217 a, 217 b, 219 a, and 219 b.

An upper end portion of the piping 215 a is connected to the front oilchamber 240 a. An upper end portion of the piping 215 b is connected tothe rear oil chamber 240 b.

The solenoid valve 216 is connected respectively to a lower end side ofthe piping 215 a and a lower end side of the piping 215 b. The solenoidvalve 216 is an example of the “valve” according to a preferredembodiment of the present invention. The solenoid valve 216 is connectedto the scavenge pump 235 via the piping 217 b, the regulator 218, andthe piping 219 a.

The solenoid valve 216 is capable of switching among a first state ofallowing the oil delivered from the scavenge pump 235 to flow into thepiping 215 a, a second state of allowing the oil to flow into the piping215 b, and a third state of not allowing the oil to flow into either ofthe piping 215 a and 215 b. In the first state, the solenoid valve 216allows the oil to flow into the front oil chamber 240 a of the hydrauliccylinder 214. In the second state, the solenoid valve 216 allows the oilto flow into the rear oil chamber 240 b. In the third state, thesolenoid valve 216 does not allow the oil to flow into either of oilchambers 240 a and 240 b.

Accordingly, when the oil flows from the scavenge pump 235 into thefront oil chamber 240 a, the piston portion 241 is moved to the rear(BWD arrow direction) side. The piston portion 241 is arranged to beable to move the rod portion 242 to the rear in this process. Therearward movement of the rod portion 242 is transmitted to the linkmechanism 245, and the link mechanism 245 moves the wire cable 211forward. The bucket 10 can thereby be moved to the forward driveposition D.

On the other hand, when the oil flows from the scavenge pump 235 intothe rear oil chamber 240 b, the piston portion 241 is moved to the front(FWD arrow direction) side. The piston portion 241 is arranged to beable to move the rod portion 242 to the front in this process. Theforward movement of the rod portion 242 is transmitted to the linkmechanism 245, and the link mechanism 245 moves the wire cable 211rearward. The bucket 10 can thereby be moved to the reverse driveposition C.

The solenoid valve 216 is connected to the oil pan 232 a of the engine203 via the piping 217 a. The solenoid valve 216 is thereby arranged tobe able to return the oil, delivered to the solenoid valve 216 by thescavenge pump 235, to the oil pan 232 a without letting the oil flowinto the hydraulic cylinder 214.

The regulator 218 is disposed at a downstream side of the scavenge pump235 and an upstream side of the hydraulic cylinder 214 in a direction offlow of the oil from the scavenger pump 235. The regulator 218 isprovided to release the oil fed to the hydraulic cylinder 214 to the oilpan 232 a. The regulator 218 is an example of the “relief valve”according to a preferred embodiment of the present invention.

The regulator 218 is connected to the solenoid valve 216 via the piping217 b. Further, the regulator 218 is connected to the scavenge pump 235via the piping 219 a. Further, the regulator 218 is connected to the oilpan 232 a via the piping 219 b.

FIG. 18 is a perspective view for describing an arrangement of avicinity of the steering unit 222. As shown in FIG. 16 and FIG. 18, thesteering unit 222 for steering the hull 2 is disposed in front of theseat 21.

A board 226 is provided between the steering unit 222 and the seat 21.The forward drive switch 226 a is provided in the board 226. The forwarddrive switch 226 a is arranged to cause the bucket 10 to move to theforward drive position D and can be operated by the rider. The reversedrive switch 226 b is disposed near the forward drive switch 226 a. Thereverse drive switch 226 b is arranged to cause the bucket 10 to move tothe reverse drive position C and can be operated by the rider. Each ofthe forward drive switch 226 a and the reverse drive switch 226 b is anexample of the “switch” according to a preferred embodiment of thepresent invention. As shown in FIG. 15, the wiring 39 is connected toeach of the forward drive switch 226 a and the reverse drive switch 226b.

FIG. 19 is a diagram for describing an arrangement around the board 226.A bucket operation indication lamp portion 226 c, capable of displayingthe position of the bucket 10, is provided near the forward drive switch226 a and the reverse drive switch 226 b. The bucket operationindication lamp portion 226 c is an example of the “display unit”according to a preferred embodiment of the present invention.

The bucket operation indication lamp portion 226 c is provided at aposition in the board 226 that is visually recognizable by the rider.

FIG. 20 is a sectional view for describing a structure of the bucketoperation indication lamp portion 226 c. The bucket operation indicationlamp portion 226 c includes five LEDs 226 d, one LED 226 e that islarger than the LEDs 226 d, an LED holder 226 f that holds the LEDs 226d and 226 e, and a protective plate 226 g. The protective plate 226 gpreferably is formed of a light transmitting material and is arranged toprotect the LEDs 226 d and 226 e while enabling light from the LEDs 226d and 226 e to be recognized visually from the exterior.

As shown in FIG. 19, two LEDs 226 d among the five LEDs 226 d aredisposed adjacent the forward drive switch 226 a. The remaining threeLEDs 226 d and the LED 226 e are disposed at substantially equalintervals along the front/rear direction of the board 226.

The one LED 226 e that is larger than the LEDs 226 d is positionedadjacent the reverse drive switch 226 b. The LEDs 226 d and 226 e arerespectively arranged to be lit (optically indicate) in correspondenceto the position of the bucket 10 (see FIG. 15) during its movementbetween the reverse drive position C (see FIG. 15) and the forward driveposition D (see FIG. 16).

Referring to FIG. 19, a notification lamp portion 226 h is provided nearboth the forward drive switch 226 a and the reverse drive switch 226 b.The notification lamp portion 226 h is arranged to be lit when theforward drive switch 226 a or the reverse drive switch 226 b is operatedby the rider when the rotational speed of the engine 203 is not lessthan a predetermined value (approximately 1250 rpm, for example). Thatthe bucket 10 is not moved is thereby notified to the rider.

FIG. 21 is a block diagram for describing an electrical arrangementrelated to the ECU 38 of the water jet propulsion watercraft 200according to the second preferred embodiment of the present invention.

The forward drive switch 226 a and the reverse drive switch 226 b arerespectively connected to the ECU 38. When each of the forward driveswitch 226 a and the reverse drive switch 226 b is operated, a signalfrom the corresponding forward drive switch 226 a or reverse driveswitch 226 b is input into the ECU 38.

The LEDs 226 d and 226 e and an LED 226 i of the notification lampportion 226 h are respectively connected to the ECU 38. The ECU 38respectively controls the LEDs 226 d and 226 e and the LED 226 i of thenotification lamp portion 226 h.

Besides the above, the arrangement of the second preferred embodiment isthe same as that of the first preferred embodiment of the presentinvention.

Operations performed when the bucket 10 is moved shall now be describedin detail. First, the operations performed when the bucket 10 is movedfrom the forward drive position D to the reverse drive position C shallbe described with reference to FIG. 13.

When the rider operates the reverse drive switch 226 b or thedeceleration aid lever 27 in the state where the bucket 10 is positionedat the forward drive position D (step S1: YES), the ECU 38 determineswhether the rotational speed of the engine 203 is less than thepredetermined value or not less than the predetermined value (step S2).

If the rotational speed of the engine 203 is not less than thepredetermined value (step S2: not less than predetermined value), theECU 38 lights up the LED 226 i of the notification lamp portion 226 hand causes the speaker 28 to generate sound (step S3). The ECU 38thereby notifies to the rider that the bucket 10 is not displaced fromthe forward drive position D.

The ECU 38 then controls the rotational speed of the engine 203 to a lowrotational speed less than the predetermined value (step S4). The ECU38, for example, controls the throttle valve motor 62 to close thethrottle valve and reduce the rotational speed of the engine 203.

The ECU 38 waits while the rotational speed of the engine 203 is notless than the predetermined value (step S5: not less than predeterminedvalue). When the rotational speed of the engine 203 becomes less thanthe predetermined value (step S5: less than predetermined value), theECU 38 turns off the LED 226 i of the notification lamp portion 226 hand stops the generation of sound by the speaker 28 (step S6).

After the LED-OFF and sound-OFF control in step S6 or after it has beenjudged in step S2 that the rotational speed of the engine 203 is lessthan the predetermined value, the ECU 38 performs a control ofdisplacing the bucket 10 from the forward drive position D to thereverse drive position C (step S7).

Specifically, with reference to FIG. 13 and FIG. 15, the ECU 38 controlsthe solenoid valve 216 to cause the oil to flow from the scavenge pump235 into the rear oil chamber 240 b of the cylinder portion 240 of thehydraulic cylinder 214. In this process, the oil flowing out from thefront oil chamber 240 a is returned to the oil pan 232 a.

More specifically, the ECU 38 controls the solenoid valve 216 to switchthe path of the oil. Switching is thereby performed from a state wherethe oil, which is delivered from the scavenge pump 235 and via theregulator 218, is returned to the oil pan 232 a from the piping 217 a toa state where the oil flows into the rear oil chamber 240 b of thecylinder portion 240. The oil thereby flows into the rear oil chamber240 b.

With the inflow of the oil into the rear oil chamber 240 b, the pistonportion 241 is moved in the FWD arrow direction. The oil is therebyreturned from the front oil chamber 240 a to the solenoid valve 216, andthe oil that is returned to the solenoid valve 216 is returned to theoil pan 232 a via the piping 217 a.

With the movement of the piston portion 241 in the FWD arrow direction,the rod portion 242 is moved in the FWD arrow direction. By the rodportion 242 being moved in the FWD arrow direction, the link mechanism245 moves the wire cable 211 in the BWD arrow direction. Consequently,the bucket 10 is rotated so as to be positioned to the rear of thedeflector 9 and the bucket 10 is thereby moved to the reverse driveposition C.

Based on the position of the rod portion 242 detected by the strokesensor 244 at this time, the ECU 38 determines the position of thebucket 10 and performs control of lighting up the LEDs 226 d accordingto the position of the bucket 10 (step S8). While the bucket 10 is beingdisplaced, the ECU 38 lights up just a corresponding number of the LEDs226 d, and when the bucket 10 reaches the reverse drive position C, theECU 38 lights up the LED 226 e adjacent to the reverse drive switch 226b.

The processes of steps S9 and S10 are the same as those of the firstpreferred embodiment of the present invention.

The operations performed when the bucket 10 is moved from the reversedrive position C to the forward drive position D shall be described withreference to FIG. 14.

When the rider presses the forward drive switch 226 a in the state wherethe bucket 10 is positioned at the reverse drive position C (step R1:YES), the ECU 38 determines whether the rotational speed of the engine203 is less than the predetermined value or not less than thepredetermined value (step R2). If the rotational speed of the engine 203is not less than the predetermined value (step R2: not less thanpredetermined value), the ECU 38 lights up the LED 226 i of thenotification lamp portion 226 h and causes the speaker 28 to generatesound (step R3). The ECU 38 thereby notifies to the rider that thebucket 10 is not displaced from the reverse drive position C.

At the same time, the ECU 38 controls the rotational speed of the engine203 to a low rotational speed less than the predetermined value (stepR4). The ECU 38, for example, controls the throttle valve motor 62 toclose the throttle valve and reduce the rotational speed of the engine203.

The ECU 38 waits while the rotational speed of the engine 203 is notless than the predetermined value (step R5: not less than predeterminedvalue). When the rotational speed of the engine 203 becomes less thanthe predetermined value (step R5: less than predetermined value), theECU 38 turns off the LED 226 i of the notification lamp portion 226 hand stops the generation of sound by the speaker 28 (step R6).

After the LED-OFF and sound-OFF control in step R6 or after it has beenjudged in step R2 that the rotational speed of the engine 203 is lessthan the predetermined value, the ECU 38 performs a control ofdisplacing the bucket 10 from the reverse drive position C to theforward drive position D (step R7).

Specifically, with reference to FIG. 14 and FIG. 16, the ECU 38 controlsthe solenoid valve 216 to cause the oil to flow from the scavenge pump235 into the front oil chamber 240 a of the cylinder portion 240 of thehydraulic cylinder 214. In this process, the oil flowing out from therear oil chamber 240 b is returned to the oil pan 232 a.

More specifically, the ECU 38 controls the solenoid valve 216 to switchthe path of the oil. Switching is thereby performed from a state wherethe oil, delivered from the scavenge pump 235 via the regulator 218, isreturned to the oil pan 232 a from the piping 217 a to a state where theoil flows into the front oil chamber 240 a of the cylinder portion 240via the piping 215 a. The oil thereby flows into the front oil chamber240 a.

With the inflow of the oil into the front oil chamber 240 a, the pistonportion 241 is moved in the BWD arrow direction. The oil is therebyreturned from the rear oil chamber 240 b to the solenoid valve 216 viathe piping 215 b. The oil that is returned to the solenoid valve 216 isreturned to the oil pan 232 a via the piping 217 a.

With the movement of the piston portion 241 in the BWD arrow direction,the rod portion 242 is moved in the BWD arrow direction. The linkmechanism 245 thereby moves the wire cable 211 in the FWD arrowdirection. Consequently, the bucket 10 is rotated so as to be positionedto above the deflector 9 and the bucket 10 is moved to the forward driveposition D.

Based on the position of the rod portion 242 detected by the strokesensor 244 at this time, the ECU 38 determines the position of thebucket 10 and performs control of lighting up the LEDs 226 d accordingto the position of the bucket 10 (step R8). While the bucket 10 is beingdisplaced, the ECU 38 turns off the LED 226 e adjacent to the reversedrive switch 226 b and lights up just a corresponding number of the LEDs26 d. When the bucket 10 reaches the forward drive position D, the ECU38 lights up the single LED 26 d adjacent to the forward drive switch226 a.

The processes of steps R9 and R10 are the same as those of the firstpreferred embodiment of the present invention.

As described above, in the second preferred embodiment of the presentinvention, the hydraulic cylinder 214 is disposed at the rear relativeto the engine 203. The hydraulic cylinder 214 can thereby be disposedclose to the bucket 10, and the wire cable 211 connecting the hydrauliccylinder 214 to the bucket 10 can be made short. By the wire cable 211being made short, an installation space for the wire cable 211 insidethe hull 2 can be made small.

Further, in the second preferred embodiment of the present invention,the link mechanism 245 is arranged to move the wire cable 211 in thedirection opposite the movement direction of the rod portion 242 of thehydraulic cylinder 240 as described above. A movement distance of thebucket 10 can thereby be adjusted based on adjustment of a length of thelink mechanism 245.

It is to be understood that the preferred embodiments disclosed hereinare by all means illustrative and not restrictive. The scope of thepresent invention is defined by the claims and not by the precedingdescription of the preferred embodiments, and all changes that fallwithin the metes and bounds of the claims or equivalence of such metesand bounds are therefore intended to be embraced by the claims.

For example, with each of the first and second preferred embodiments ofthe present invention, although an arrangement where the rod portion 142or 242 of the hydraulic cylinder 14 or 214 moves in the substantiallyfront/rear direction of the hull 2 was described, the present inventionis not restricted thereto. For example, each of the rod portions 142 and242 may move in the right/left direction of the hull 2 instead.

With each of the first and second preferred embodiments of the presentinvention, an example where the scavenge pump 35 or 235 of the engine 3or 203 is used to cause the oil to flow into the corresponding hydrauliccylinder 14 or 214 was described, the present invention is notrestricted thereto. For example, the oil delivered from the feed pump 34of the engine 3 or 203 may be arranged to flow into the correspondinghydraulic cylinder 14 or 214. The present invention is not restricted tothe oil pump provided inside of the engine 3 or 203, and an electricpump or other pump for causing the oil flow into the hydraulic cylinder14 or 214 may be provided separately. In a case where the scavenge pump35 or 235 is not to be used as the pump for the corresponding hydrauliccylinder 14 or 214, the scavenge pump 35 or 235 may be omitted. In thiscase, the oil from the feed pump 34 or the like is arranged to besupplied to the hydraulic cylinder 14 or 214.

In each of the first preferred embodiment and the second preferredembodiment of the present invention, the bucket 10 may be arranged to bemoved from the reverse drive position A or C to the forward driveposition B or D in a case where the bucket 10 is positioned at thereverse drive position A or C when the engine 3 or 203 is started.

In each of the first preferred embodiment and the second preferredembodiment of the present invention, the oil may be arranged to besupplied to the corresponding hydraulic cylinder 14 or 214 when therotational speed of the engine 3 or 203 is not less than a predeterminedvalue.

With each of the first and second preferred embodiments, although anexample of applying the oil pan 32 a or 232 a, provided in the crankcase32 or 232 of the engine 3 or 203, as an example of the oil storageportion according to a preferred embodiment of the present invention wasdescribed, the present invention is not restricted thereto. An oilstorage portion other than an oil pan provided in the crankcase may beapplied, for example, by providing an oil tank that stores engine oil ata position that differs from the crankcase of the engine, etc.

With the first preferred embodiment, although an example where thehydraulic cylinder 14 is supported by the engine 3 was described, thepresent invention is not restricted thereto. For example, the hydrauliccylinder 14 may instead be supported by the hull 2.

With the first preferred embodiment, although an example where thehydraulic cylinder 14 is supported by the upper portion of the engine 3was described, the present invention is not restricted thereto. Forexample, the hydraulic cylinder 14 may instead be supported by a lowerportion of the engine 3.

With each of the first and second preferred embodiments, although anexample where the direction in which the wire cable 11 or 211 is pushedand pulled is substantially parallel to the axial direction of thecylinder portion 140 or 240 was described, the present invention is notrestricted thereto. For example, the direction in which the wire cable11 or 211 is pushed and pulled may intersect (be perpendicular orsubstantially perpendicular to) the axial direction of the cylinderportion 140 or 240.

With each of the first and second preferred embodiments, although anexample where the hydraulic cylinder 14 or 214 is disposed upwardrelative to the lower end portion of the air ventilation hose 5 wasdescribed, the present invention is not restricted thereto. For example,the hydraulic cylinder 14 or 214 may instead be disposed downwardrelative to the lower end portion of the air ventilation hose 5.

With the second preferred embodiment, although an example where thehydraulic cylinder 214 is disposed at the rear relative to the engine203 was described, the present invention is not restricted thereto. Forexample, the hydraulic cylinder 214 may instead be disposed at the rightside or the left side of the engine 203 or be disposed in front of theengine 203.

With each of the first and second preferred embodiments, although anexample where the spring member 12 is used to hold the bucket 10 at theforward drive position B or D was described, the present invention isnot restricted thereto. For example, the spring member 12 may beomitted. In this case, in place of the spring member 12, an engagingmember including an engaging portion and an engaged portion may beapplied as the position holding member, or an arrangement may be made tohold the bucket 10 by a magnet at the forward drive position B or D.

With the first preferred embodiment, although an example where theportion of the rod portion 142 of the hydraulic cylinder 14 that ishoused inside the cylinder portion 140 is greater when the bucket 10 isat the forward drive position B than when the bucket 10 is at thereverse drive position A was described, the present invention is notrestricted thereto. For example, the portion of the rod portion 142 thatis housed inside the cylinder portion 140 may be greater when the bucket10 is at the reverse drive position A than when the bucket 10 is at theforward drive position B.

With the second preferred embodiment, although an example where theportion of the rod portion 242 of the hydraulic cylinder 214 that ishoused inside the cylinder portion 240 is greater when the bucket 10 isat the forward drive position D than when the bucket 10 is at thereverse drive position C was described, the present invention is notrestricted thereto. For example, the portion of the rod portion 242 thatis housed inside the cylinder portion 240 may be greater when the bucket10 is at the reverse drive position C than when the bucket 10 is at theforward drive position D.

With each of the first and second preferred embodiments, although anexample where the stroke sensor 144 or 244, which detects the strokeamount of the rod portion 142 or 242 of the hydraulic cylinder 14 or214, is provided to detect the position of the bucket 10 was described,the present invention is not restricted thereto. For example, a positionsensor for detecting the position of the bucket 10 may be provideddirectly on the bucket 10.

With the first preferred embodiment, although an example where thedeceleration aid lever 27 is gripped while gripping the acceleratorlever 23 a to decelerate the water jet propulsion watercraft 1 wasdescribed, the present invention is not restricted thereto. For example,when the deceleration aid lever 27 is operated, the engine rotationalspeed may be increased automatically to a predetermined speed when thebucket 10 completes the movement to the reverse drive position Aregardless of the operation state of the accelerator lever 23 a. In thiscase, it suffices to operate just the deceleration aid lever 27 when thewater jet propulsion watercraft 1 is to be decelerated, and theoperation by the rider can thus be simplified.

In regard to detection of input to the deceleration aid lever 27, apotentiometer or a load sensor (for example, a magnetostrictive sensor)may be provided in place of the switch. It thereby becomes possible toprovide an arrangement where the increase of the rotational speed of theengine is controlled according to the input of the rider to thedeceleration aid lever 27 (amount or strength of grip by the rider). Itthereby becomes possible for the rider to readily adjust the degree ofdecelerate of the water jet propulsion watercraft 1.

While preferred embodiments of the present invention have been describedabove, it is to be understood that variations and modifications will beapparent to those skilled in the art without departing the scope andspirit of the present invention. The scope of the present invention,therefore, is to be determined solely by the following claims.

The present application corresponds to Japanese Patent Application No.2008-315961 filed in the Japan Patent Office on Dec. 11, 2008, and theentire disclosure of the application is incorporated herein byreference.

1. A water jet propulsion watercraft comprising: a hull; an engineattached to the hull; a jet propulsion device arranged to be drivenusing an output of the engine and to jet water toward a rear of the hullfrom a jet port provided on an outer side of the hull; a bucket arrangedto be movable between a forward drive position of not blocking the waterjetted from the jet port of the jet propulsion device and a reversedrive position of blocking the water jetted from the jet port and, atthe reverse drive position, to convert a jetting direction of the waterjetted rearward from the jet port to a forward direction; a hydrauliccylinder disposed in an interior of the hull and arranged to move thebucket between the forward drive position and the reverse driveposition; and an oil passage arranged to connect the engine and thehydraulic cylinder and to cause a lubricating oil inside of the engineto pass through as a hydraulic oil of the hydraulic cylinder.
 2. Thewater jet propulsion watercraft according to claim 1, further comprisinga cable arranged to transmit a driving force of the hydraulic cylinderto the bucket.
 3. The water jet propulsion watercraft according to claim1, wherein the hydraulic cylinder includes a cylinder portion, a pistonportion arranged to slide along an inner wall of the cylinder portion,and a rod portion connected to the piston portion, and the rod portionis arranged to move along a substantially front/rear direction of thehull.
 4. The water jet propulsion watercraft according to claim 1,wherein the engine includes a crankshaft and an oil pump arranged to bedriven using a rotation of the crankshaft and to circulate thelubricating oil inside the engine, and the oil pump is arranged to feedthe lubricating oil to the hydraulic cylinder.
 5. The water jetpropulsion watercraft according to claim 4, further comprising an oilstorage portion arranged to store the lubricating oil therein, and arelief valve arranged to be able to pass the lubricating oil fed to thehydraulic cylinder by the oil pump to the oil storage portion.
 6. Thewater jet propulsion watercraft according to claim 5, wherein the oilstorage portion is provided at a lower portion of the engine and belowthe relief valve.
 7. The water jet propulsion watercraft according toclaim 5, wherein the oil pump includes a first oil pump arranged todeliver the lubricating oil from the oil storage portion to an inside ofthe engine to lubricate the inside of the engine, and a second oil pumparranged to deliver the lubricating oil that has lubricated the insideof the engine into the oil storage portion, and the second oil pump isarranged to have a lower discharge pressure than a discharge pressure ofthe first oil pump and is arranged to feed the lubricating oil to thehydraulic cylinder.
 8. The water jet propulsion watercraft according toclaim 1, wherein the hydraulic cylinder includes a cylinder portion, anda piston portion arranged to be slidable along an inner wall of thecylinder portion and to be driven to displace the bucket between theforward drive position and the reverse drive position, and the water jetpropulsion watercraft further comprises a valve disposed in the oilpassage and arranged to change a drive direction of the piston portionby changing a flow direction of the lubricating oil in the oil passage,and a switch arranged to be operable by a rider, and the valve isarranged to change the drive direction of the piston in response to theoperation of the switch.
 9. The water jet propulsion watercraftaccording to claim 8, further comprising a control unit arranged tocontrol the valve and the engine, and a rotational speed detection unitarranged to detect a rotational speed of the engine, wherein the controlunit is arranged to lower the rotational speed of the engine to lessthan a predetermined value and thereafter control the valve to changethe drive direction of the piston portion when the rotational speed ofthe engine is not less than the predetermined value and the rideroperates the switch.
 10. The water jet propulsion watercraft accordingto claim 1, wherein the hydraulic cylinder is disposed near the enginein an interior of the hull.
 11. The water jet propulsion watercraftaccording to claim 1, wherein the hydraulic cylinder is supported by theengine.
 12. The water jet propulsion watercraft according to claim 1,wherein the hydraulic cylinder is disposed inward relative to both sidesof the engine in a width direction of the engine in plan view.
 13. Thewater jet propulsion watercraft according to claim 1, wherein thehydraulic cylinder is supported by an upper portion of the engine. 14.The water jet propulsion watercraft according to claim 2, wherein adirection in which the cable is pushed and pulled by the hydrauliccylinder is substantially parallel to an axial direction of the cylinderportion of the hydraulic cylinder.
 15. The water jet propulsionwatercraft according to claim 1, further comprising a seat to bestraddled by a rider, wherein the hydraulic cylinder is disposed belowthe seat.
 16. The water jet propulsion watercraft according to claim 1,further comprising an air introduction portion arranged to introduce airinto an interior of the hull, the air introduction portion extendingfrom an upper portion of the hull to below the interior of the hull inwhich the engine is disposed, wherein the hydraulic cylinder is disposedupward relative to a lower end portion of the air introduction portion.17. The water jet propulsion watercraft according to claim 1, whereinthe hydraulic cylinder is disposed at rearward of the engine.
 18. Thewater jet propulsion watercraft according to claim 1, further comprisinga position holding member arranged to hold the bucket at the forwarddrive position.
 19. The water jet propulsion watercraft according toclaim 1, wherein the hydraulic cylinder includes a cylinder portion, apiston portion arranged to slide along an inner wall of the cylinderportion, and a rod portion connected to the piston portion, and aportion of the rod portion that is housed inside the cylinder portion isgreater when the bucket is at the forward drive position than when thebucket is at the reverse drive position.
 20. The water jet propulsionwatercraft according to claim 2, wherein the hydraulic cylinder includesa cylinder portion, a piston portion arranged to slide along an innerwall of the cylinder portion, and a rod portion connected to the pistonportion, and the water jet propulsion watercraft further comprises alink mechanism connected to the rod portion of the hydraulic cylinderand the cable and arranged to move the cable in a direction opposite toa movement direction of the rod portion.